Sound Level Meter Baaska

bb090913.book : Front Black 1

November 1996

Brüel & Kjær BB0909–13

Precision IntegratingSound Level Meter

Type 2236 A – 009Type 2236 B – 009Type 2236 C –009Type 2236 D – 009

With software version 2.1 or higher

Revision

bb090913.book : Front Black 2

0 – 2 Brüel & KjærPrecision Integrating Sound Level Meter Type 2236User Manual

Trademarks

IBM is a registered trademark of International Business MachinesInc., USA

Copyright © 1993, 1996, Brüel&Kjær Sound & Vibration Measurement A/S

All rights reserved. No part of this publication may be reproducedor distributed in any form, or by any means, without prior consentin writing from Brüel & Kjær Sound & Vibration Measurment A/S,Nærum, Denmark.

bb090913.book : bb090913_TOC.doc Black 3

BB0909–13 0 – 3Precision Integrating Sound Level Meter Type 2236User Manual

4

1

Contents

Describes the sound level meter and its general operating principles.

A familiarization guide which explains, step by step, a typicalmeasurement.

How to prepare the sound level meter for measuring.

How to calibrate and measure with the sound level meter.

What you are able to do with your results.

The specifications and information regarding other equipmentavailable for use with the sound level meter.

Service and repair of the sound level meter.

Explains specific terminology used in the manual and containsinstructions on how to control the sound level meter from acomputer.

Useful Information

2An Example Measurement

3Setting Up the SLM for Measurement

Measuring

5Storing and Transferring Results

6Specifications

7Service and Repair

8Appendices

bb090913.book : bb090913_TOC.doc Black 4


Index

FoldOut

Controls, Display and SocketsAn overview of the sound level meter’s pushkeys, controls and maindisplay.

bb090913.book : 2236-ch1_TOC.doc Black,Blue 1


Chapter 1

Useful Information

1.1 About this Manual .............................................................. 1 – 2

1.2 About the Type 2236 Sound Level Meter................. 1 – 2

Parameters......................................................................... 1 – 2Settings .............................................................................. 1 – 3Data Operations ................................................................ 1 – 7Memory .............................................................................. 1 – 9

1.3 Practical Hints.................................................................... 1 – 10

bb090913.book : 2236-ch1 Black 2

Chapter 1 – Useful InformationAbout this Manual


1.1 About this Manual

Figures are used to guide you through using the pushkeys.Please note the following when using the figures:

n× Press this pushkey n times

OK Press this to save any changes made in connection withthe Settings or ⟨ Data ⟩ pushkeys

NO Press this to return to the screen indicated without sav-ing any changes made

1.2 About the Type 2236 Sound LevelMeter

1.2.1 Parameters

Precision Integrating Sound Level Meter Type 2236 is a Type1 sound level meter complying with BS 5969 and BS 6698. Itcan measure the following parameters:

MaxL: maximum SPL since the last reset

MinL: minimum SPL since the last reset

MaxP: maximum Peak level since the last reset

Peak: maximum Peak level in 1s interval

SPL: maximum RMS level in 1s interval (according toIEC 651)

Leq: equivalent continuous sound level (Leq according toIEC 804)

LIm: equivalent continuous impulse sound level (if timeweighting is I) (LIm according to IEC 804, Appendix B)

SEL: Sound Exposure Level (if A-weighted, then = LEA,according to IEC 804)

IEL: Impulse Sound Exposure Level (if time weighting isI)


Chapter 1 – Useful InformationAbout the Type 2236 Sound Level Meter


LEPd: Daily Personal Noise Exposure Level (see section8.2)*

LN(3) (default L90): RMS level exceeded N3% of the meas-urement time (LN(3))

†


†


†

OVL: Input signal overloading instrument (% of the meas-urement time)

In addition, Precision Integrating Sound Level Meter Types2236 C–009 and 2236 D–009 contain 1/1-octave filter setsbetween 31.5 Hz and 8 kHz which comply with BS 2475(1964). They can measure all the above-mentioned parame-ters in each of the filter bands.

1.2.2 Settings

Checking and Changing the Settings

The sound level meter’s Settings are additional to the basicmeasurement set-up. They are very useful and are based ona very simple principle (see the example in Fig. 1.1). Thereare eleven of them in all:

Auto Logging

Calibration

Peak Weighting

Date and Time

Auto Start

Change Range Reset

Contrast

Percentiles

* Not available with I time weighting† Not available with I time weighting




Exposure Time

Interface

Output Formats

Checking

You can check the first of the sound level meter’s Settings bypressing the ⟨ Show ⟩ pushkey. You can then step throughthem by pressing ⟨ Show ⟩. However, the Settings are cyclicand you can step forwards and backwards through them us-ing Parameter ⟨ ⟩ and ⟨ ⟩, respectively (see Fig. 1.1).

Changing

When you reach a Setting you want to change, press ⟨ Edit ⟩.A cursor ( ) appears on the first set-up line you can change.

Fig.1.1 Principle of checking and changing the sound level meter’s Set-tings

931085/1e

Edit

EditParameter

Level

Levelor Parameter

Show or Parameter

Show

Parameter

PreviousSetting

Previousparameter

NextSetting

Nextparameter

AUTO LOGGING

-every 1 s.

(Leq L10 L90)

to log

AUTO LOGGING

-every 1 s.

(Leq L10 L90)

to log

30 .... 110

00:00:00

F SPL 58.6 dBA




If there are other set-up lines on the screen, you can movethe cursor to them using Level ⟨ ⟩ and ⟨ ⟩.

When the cursor is on the set-up line of the Setting you wantto change, press Parameter ⟨ ⟩ and ⟨ ⟩ to step throughthe available parameters. You can also step through them bypressing ⟨ Edit ⟩ (see Fig. 1.1).

When you have the set-up you desire for that Setting, press⟨ OK ⟩ to save the changes and check the changed Setting. Anaccept cursor ( ) replaces the edit cursor ( ) to show that thesound level meter has accepted the change.

If you change a Setting by mistake, press ⟨ NO ⟩ instead of⟨ OK ⟩ to revert to its previous set-up.

Fig. 1.2 shows an overview of the available Settings.




Fig.1.2 An overview of the sound level meter’s Settings

931084/2e

AUTO LOGGINGOUTPUT FORMATS

INTERFACE

EXPOSURE TIME

PERCENTILES

CONTRAST

CALIBRATION

PEAK WEIGHTING

DATE/TIME

AUTO START

CHANGE RANGE

OK

OK

Show

ShowShow

OK Show

OK Show

OK Show

OK Show

OK Show

OKShow

OKShow

OKShow

OKShow

30 .... 110

PAUSE 00:00:00F SPL 58.6 dBA

NO

NO NO

NO

NO

NO

NO

NO

NO

NO

NO




Fast Edit

In addition to the normal way of changing the set-up of aSetting (that is, pressing ⟨ Show ⟩, stepping through to thedesired “Setting” and pressing ⟨ Edit ⟩), you can also use twopushkeys together to “fast edit” a Setting (that is, go directlyto a Setting with the edit cursor).

If you press ⟨ Edit ⟩ and, within three seconds, the pushkeyindicated in Table 1.1, the selected Setting appears with theedit cursor ( ). You can now check and change the set-up ofthe Setting as described earlier in this section. When youhave finished changing the Setting, pressing ⟨ NO ⟩ or ⟨ OK ⟩,however, returns you to the main screen.

1.2.3 Data Operations

The sound level meter’s ⟨ Data ⟩ pushkey allows you to printyour measurement results (data) and control the sound levelmeter’s memory. It operates on a similar principle as Settings(see section 1.2.2) except that you press ⟨ Data ⟩ instead of⟨ Show ⟩. In addition, the sound level meter returns to the

Fast Edit Pushkey (Edit +) ... ... Goes to Setting

Level or Parameter or (Disp. param.: Peak, MaxP)Parameter or (Disp. param.: LN)Parameter or (Disp. param.: LEP,d)Data

OK

CalibrationPeak Frequency WeightingPercentilesExposure TimeOutput FormatsChange Range with ResetContrastAuto StartStatus (only via Fast Edit)

Table 1.1 Fast edit pushkeys and the Settings accessed. Where displayparameters are shown in parenthesis (for example, (Disp. par-am.: LN)), then the display must be showing the indicatedparameter (in this example, LN) when the Fast Edit keys arepressed to go to the indicated setting (in this example, Percen-tiles)

0




main screen after you have accepted changes to the selectedoperation. There are four data operations, each with its ownscreen:

Print

Store

Recall

Erase

Fig. 1.3 shows an overview of the data operations.

Fig.1.3 An overview of the data operations available via the Data push-key

930791/2e

OK

Data

Data

OKData

30 .... 110


PRINT

STORE

Data

OK

OK

Data

ERASE

RECALL

NO

NO

NO

NO




1.2.4 Memory

The sound level meter has three types of memory:

Buffer

Log

Memory

Buffer

Contains the set-up and all results for the current measure-ment (i.e. since the last reset) – see section 1.2.1. From these,the cumulative and level distributions and the Overall Re-sults are calculated. The buffer is updated once a second.

Log

Contains the automatically Logged Results (see section 5.5.2):

Leq

L10

L90

measurement time of results (if logging period is not0.1 sec)

Precision Integrating Sound Level Meter Types 2236 A–009and C–009 can contain up to 21600 sets of results (i.e. up to64800 results with their measurement times). This is enoughto log, for example, 2months of Leq, L10 and L90 values loggedevery 5 minutes.

Precision Integrating Sound Level Meter Types 2236 B–009and D–009 can contain up to 86400 sets of results (i.e. upto 259200 results with their measurement times). This isenough to log, for example, 8months of Leq, L10 and L90values logged every 5 minutes.

Memory

Contains the Overall Results which you have manually storedin a Record together with the set-up. Can contain up to 40Records.

bb090913.book : 2236-ch1 Black 10

Chapter 1 – Useful InformationPractical Hints


Overall Results consist of:

Note: The three LN values in Overall Results are fixed asthe selected LNs when the results were stored. You can, there-fore, only see these three LN values after recalling OverallResults.

1.3 Practical Hints

The sound level meter is designed as a self-contained unit tomeet the requirements given in IEC 651 and similar nationalstandards. However, some of the requirements given in thestandards are based on measurements of pure tones underfree field conditions. Practical measurements under similarconditions require the following extra precautions:

Do not stand close to the sound level meter

Do not use a windscreen or protective cover

Using a microphone extension cable, increase the dis-tance between the microphone and any objects which cancause disturbances

MaxL

MinL

MaxP

Leq (or LIm)

SEL (or IEL)

LEP,d

Exposure Time

Ovl

LN1 (default L1)

LN2 (default L10)

LN3 (default L90)

Frequency weighting of RMSsignal

Frequency weighting of Peaksignal

Time weighting

Measurement range

Elapsed measurement time

Start date and time of meas-urement

Number of pauses duringmeasurement

bb090913.book : 2236-ch1 Black 11

Chapter 1 – Useful InformationPractical Hints


The influence of your presence on the measurement can easilybe checked by changing the distance between you and themicrophone and observing the change in the measured soundpressure level. If your position influences the measurementresult, then use a microphone extension cable or spatiallyaverage your measurements (that is, measure at differentpositions and average the results). Note that, when dealingwith pure tones, a small change in the position of the micro-phone can influence the result just as much as your physicalpresence.

Fortunately, the combination of free sound field and puretones is very rare. With sound coming from several directionsand as you are measuring over a broad frequency band, theinfluence of the sound level meter’s housing, tripod and userbecomes insignificant, and the above precautions need not betaken.

Figs. 6.8 and 6.9 show the influence of Tripod UA 0801 andProtective Cover UA 1236 under free field conditions and withpure tones.

bb090913.book : 2236-ch1 Black 12




Chapter 2

An Example Measurement

2.1 Introduction ........................................................................... 2 – 2

2.2 Making a Measurement ................................................... 2 – 2


Chapter 2 – An Example MeasurementIntroduction


2.1 Introduction

This chapter guides you through the basic functions of thesound level meter by instructing you on how to make a noisemeasurement in a free sound field. You can find further in-formation on the various steps in the relevant sections of theUser Manual.

It is a good idea to have the fold-out back cover open so thatyou have an annotated illustration of the sound level meterin front of you while you follow the example measurement.

We have assumed that the sound level meter is switched offand has not been used before following these instructions. Ifit has, ensure that you are using the default set-up (seesection 3.3) before following the steps below.

We have also assumed that you will calibrate the sound levelmeter with Sound Level Calibrator Type 4231 and that youwill print out your results using Serial Printer WQ 1138.

2.2 Making a Measurement

Switching On

1. Press .

The sound level meter switches on. After a self-test, thesound level meter is set up in Pause mode in the defaultset-up. The quasi-analogue scale shows the input signalto the preamplifier and displayed parameter shows thecurrent SPL. The buffer, log and memory are empty.

Since the displayed parameter (SPL) is an RMS param-eter, you can see the frequency weighting of the RMSsignal (shown in the bottom right-hand corner of thescreen). See the fold out back cover for more details ofthe main screen.


Chapter 2 – An Example MeasurementMaking a Measurement


Calibrating the Sound Level Meter

2. Press ⟨ Show ⟩.

The screen shows the default Auto Logging screen.

3. Press Parameter ⟨ ⟩.

The screen changes to the Calibration screen. It showsthe current calibration factor.

4. Press ⟨ Edit ⟩.

The screen shows the calibration set-up (see Fig. 2.1).

5. Read the correct calibration level from the calibrator’scalibration chart and use Parameter ⟨ ⟩ and ⟨ ⟩ to setthe sound level meter to this level.*

6. Fit the calibrator onto the sound level meter and rest thesound level meter on a table or other flat surface. Ensurethat the calibrator fits snugly on the microphone.

7. Switch on the calibrator.

The calibrator emits the 1 kHz calibration signal.

8. Press ⟨ OK ⟩.

* Sound Level Calibrator Type 4231 provides a nominal calibration signal of 94dB at 1 kHz.However, each calibrator is slightly different. It is, therefore, important to set the calibrationlevel to the one given on the calibration chart for the calibrator used.

Fig.2.1 The calibration set-up screen

930989/1e

CALIBRATIONCalibr. level:94.0 dB




The sound level meter checks the calibration signalagainst the calibration level you set in step 5. It thenasks if you want to calibrate according to the expectedlevel.


The sound level meter calibrates itself according to thecalibration level you set in step 5 and returns to theCalibration screen, which now shows the new calibrationfactor.


The sound level meter returns to the main screen.

Checking the Weightings

11. With sound level meters without filter sets (Types2236 A–009 and 2236 B–009), press ⟨ Frequency Wt. ⟩three times.

The frequency weighting of the RMS signal (displayed inthe bottom right-hand corner of the screen) changesthrough the three available weightings.

12. With sound level meters with filter sets (Types2236 C–009 and 2236 D–009), press ⟨ Frequency Wt. ⟩twelve times.

The frequency weighting of the RMS signal (displayed inthe bottom right-hand corner of the screen) changesthrough the three available total weightings and the nineavailable octave filters (displayed at the left-hand side ofthe screen under the quasi-analogue scale). It then re-turns to the original frequency weighting of the RMSsignal.

13. Press ⟨ F/S/I ⟩ three times.

The time weighting displayed in the bottom left-handcorner of the screen changes through the three availableweightings.




Setting up the Sound Level Meter to Log

14. Press ⟨ Show ⟩.

The screen shows the default Auto Logging screen (seeFig. 2.2). You can see that the sound level meter is setup so that it doesn’t store Logged Results in its log.

15. Press ⟨ Edit ⟩.

You can now set up the sound level meter to automaticallystore Logged Results in its log.


The screen changes to the Auto Logging set-up screenshown in Fig. 2.3. You can see that the sound level meteris set up to automatically store Logged Results (Leq, L10and L90) in its log every 1s.

Fig.2.2 The default Auto Logging set-up screen

Fig.2.3 One of the Auto Logging set-up screens

930990/1

AUTO LOGGINGOff

931086/1e

AUTO LOGGINGto log-every 1 s. (Leq L10 L90)




17. Press ⟨ OK ⟩ twice.

The sound level meter returns to the main screen.

You are now ready to start an A-weighted measurementof noise with a FAST time weighting. Leq, L10 and L90will be automatically logged into the sound level meter’slog.

Measuring

18. Select an appropriate measurement range using Level⟨ ⟩ or ⟨ ⟩.

An appropriate measurement range is when the signalremains on the quasi-analogue scale at all times and nooverload (indicated by + in the upper right-hand cornerof the screen) occurs.

Note: It is important to select an appropriate measure-ment range before starting to measure as, if you changethe range, either the sound level meter will reset, or thedistributions and LNs will not be available.

19. Press .

This clears the sound level meter’s buffer of results andsets the elapsed time to zero.

20. Press .

The sound level meter starts measuring. The timer onthe right-hand side of the screen starts counting theelapsed measurement time. The A-weighted SPL isshown at the bottom of the screen. After each second, theLeq, L10 and L90 are transferred to the sound level meter’slog.

21. Use Parameter ⟨⟩ or ⟨⟩ to look at the various param-eters available.

The quasi-analogue scale always shows the SPL, regard-less of the selected parameter. Note that, when a Peakparameter is selected, the frequency weighting of thePeak signal is shown. Note also that, when changing theparameter, the sound level meter does not reset.

0




22. After a few minutes, press .

The sound level meter stops measuring and logging. Thetimer shows the total measurement time.

Checking the Sound Level Meter’s Calibration

23. Press ⟨Show ⟩.

The screen shows the default Auto Logging screen.

24. Press Parameter ⟨⟩.

The screen changes to the Calibration screen.

25. Press ⟨Edit ⟩.

The screen shows the calibration set-up from before themeasurement.

26. Fit the calibrator onto the sound level meter and rest thesound level meter on a table or other flat surface. Ensurethat the calibrator fits snugly on the microphone.


The calibrator emits the 1kHz calibration signal.

28. Press ⟨OK ⟩.

The sound level meter checks the calibration signalagainst the calibration level you set in step 5. They shouldbe the same. If they are not, note the difference for in-clusion in your measurement report.

29. Press ⟨NO ⟩ twice.

The sound level meter returns to the Calibration screenand then to the main screen without being recalibrated.

Storing Results in the Sound Level Meter’s Memory

30. Press ⟨Data ⟩.

The first Data screen (Print Set-up) appears.





The Store Set-up screen (see Fig. 2.4) appears.


The Overall Results of the measurement you have justmade are stored as Record No.1 in the sound level meter’smemory.

Printing out Overall Results

Warning! When connecting the sound level meter to theprinter, ensure that both the printer and the sound levelmeter are switched off. Otherwise the instruments could bedamaged.

33. Switch the sound level meter off. Connect it to SerialPrinter WQ 1138 via the Serial Interface socket on thebase of the sound level meter using 9-pole Cable with 25-pole Adaptor AO1386.

34. Switch the sound level meter on.

35. Hold down the printer’s ⟨ On Line ⟩ pushkey and switchthe printer on.

The printer prints its set-up.

36. Ensure that the printer’s baud rate is 9600 (see the print-er’s instruction manual for details on how to change itsbaud rate).

Fig.2.4 The Store Set-up screen

930996/1e

STOREOverall Results-as Rec. No. 1




The sound level meter is set, by default, to output theoverall results with a short heading at a baud rate of9600. To get a print-out, the printer and the sound levelmeter must have the same baud rate.

37. Press ⟨ Data ⟩.

The Print Set-up screen appears (see Fig. 2.5).


The printer prints the Overall Results (see section 1.2.4)together with a short heading containing the measure-ment set-up (the frequency weightings of the RMS andPeak signals, the time weighting and the measurementrange). After transferring the results to the printer, thesound level meter displays the main screen.

Fig.2.5 The default Print Set-up screen

930997/1e

PRINTOverall Results

bb090913.book : 2236-ch2 Black 10




Chapter 3

Setting Up the SLM forMeasurement

3.1 Mounting the Microphone ............................................... 3 – 3

3.2 Fitting Batteries .................................................................. 3 – 4

Replacing Batteries ........................................................... 3 – 5Using an External Power Supply ..................................... 3 – 6The Back-up Battery ......................................................... 3 – 6

3.3 Switching the SLM On and Off..................................... 3 – 8

3.4 Setting the Measurement Range ................................. 3 – 9

3.5 Setting the Time Weighting ......................................... 3 – 11

3.6 Setting the Frequency Weighting.............................. 3 – 12

Introduction ..................................................................... 3 – 12Setting the RMS Frequency Weighting ......................... 3 – 12Setting the Peak Frequency Weighting ......................... 3 – 14


Chapter 3 – Setting Up the SLM for Measurement


3.7 Setting the Percentiles ................................................... 3 – 15

3.8 Setting the Exposure Time ........................................... 3 – 17

3.9 Setting the Date and Time............................................ 3 – 18

3.10 Setting the SLM to Change Rangewithout Resetting.............................................................. 3 – 20

3.11 Setting up Auto Logging ................................................ 3 – 21

3.12 Setting the Viewing Conditions.................................. 3 – 24


Chapter 3 – Setting Up the SLM for MeasurementMounting the Microphone


3.1 Mounting the Microphone

Before mounting the microphone, note the following precau-tions:

When screwing in the microphone, input stage, protectiongrid and extension cables, do it gently to avoid damag-ing the threads.

Do not touch the diaphragm with any object — it is verydelicate. Small amounts of dust on the diaphragm willnot affect the microphone response.

Mounting the Microphone and Input Stage

1. Gently screw Microphone Type 4188 (supplied with thesound level meter) onto Input Stage ZC 0025.

2. Insert the input stage into the input stage socket andsecure by turning the threaded retaining ring (seeFig. 3.1).

Connecting the Microphone Extension Cable

1. Gently screw Microphone Type 4188 (supplied with thesound level meter) onto Input Stage ZC 0025.

2. Insert the input stage into Microphone Extension CableAO 0408 (3 m) or AO 0409 (10 m) and secure by turningthe threaded retaining ring.

3. Insert the other end of the microphone extension cableinto the input stage socket and secure by turning thethreaded retaining ring (see Fig. 3.2).

Note: Connecting a recommended microphone extension ca-ble has no effect on the sound level meter’s calibration. There-fore, you do not have to recalibrate after connecting one ofthe recommended microphone extension cables.


Chapter 3 – Setting Up the SLM for MeasurementFitting Batteries


3.2 Fitting Batteries

Important:

Before removing batteries or disconnecting a power supplyfrom the sound level meter, make sure the instrument isswitched off from the front panel by pressing . You riskdraining the back-up battery if you remove the batteries whilethe sound level meter is switched on.

Fig.3.1 Mounting the input stage and microphone onto the sound levelmeter




3.2.1 Replacing Batteries

1. Make sure the sound level meter is switched off by press-ing .

2. Press the two tabs on the upper edge of the batterycompartment and remove the lid.

3. Replace the old batteries with new ones (four 1.5 V LR6/AA size alkaline batteries) as shown in the battery com-partment and press the compartment lid back into place.

Note: If you cannot switch on the sound level meter afterreplacing the batteries, check that they are correctly inserted.The sound level meter is designed so that it will not work if

Fig.3.2 Connecting a microphone extension cable to the sound level meter




the batteries are wrongly inserted in the battery compart-ment.

Warnings!

It is possible for batteries to explode or leak if they arehandled incorrectly, so:

For long-term storage, remove the batteries and keep thesound level meter in a dry place.

Never mix different makes or types of battery.

Never mix charged and discharged batteries.

Always label the outside of the battery compartment withthe type of batteries contained.

3.2.2 Using an External Power Supply

The sound level meter can be powered from a regulated orsmoothed 7–15 V DC supply via the External Power socketon the base (e.g. from the mains supply via an adaptor).

You can connect the external power supply even when thebatteries are installed. The sound level meter automaticallyselects the source with the highest supply voltage. The ex-ternal power supply will not damage the batteries but neitherwill it recharge the batteries.

Always switch off the sound level meter by pressing beforeunplugging the external power supply. Otherwise you riskdraining the back-up battery.

3.2.3 The Back-up Battery

The sound level meter has a back-up battery for running theclock and maintaining the memory, log and buffer, even whenthe sound level meter is switched off or the main batteriesare removed.

The back-up battery is automatically recharged when thereare batteries in the sound level meter. It is fully charged




after about 10hours. Fully charged, the back-up battery runsthe clock and retains the results for about 6months.

These charge times are typical for a sound level meter atroom temperature.

If the back-up battery is flat, the date and time will be resetto a factory set date. If you find that the date and time arewrong, this is probably the reason.


Chapter 3 – Setting Up the SLM for MeasurementSwitching the SLM On and Off


3.3 Switching the SLM On and Off

Switching the Sound Level Meter On

Press .

The sound level meter tests its memory and then returnsto Pause mode with the set-up it had when it was lastswitched off. While testing its memory, the display shows theversion of the sound level meter (e.g. 2236 A–009).

The default set-up is:

Frequency weighting (RMS): AFrequency weighting (Peak): CTime weighting: FDisplayed parameter: SPLDisplayed range: 30 – 110 dBOutput formats: Overall Results

Short HeadingLogged ResultsShort HeadingPrinter

Level DistributionShort Heading5dB resolution

Cumulative DistributionShort Heading5dB resolution

LN1: L1LN2: L10LN3: L90Auto logging: OffExposure Time: 7:30 hoursReset at range change: OnAuto start: Off

Note:

To switch the sound level meter on in the default set-up,press and hold and then press for about 1 s. The0


Chapter 3 – Setting Up the SLM for MeasurementSetting the Measurement Range


sound level meter erases all results and returns to thedefault set-up in Pause mode.* Note that this procedurewill reset your calibration. You must therefore recalibrateyour instrument as described in section 4.1 after reset-ting. We recommend that you do not reset the instrumentin this way if you are using an accredited calibration.

To erase all results in the log, memory and buffer, press and ⟨ Data ⟩.

Switching the Sound Level Meter Off

Press .

The sound level meter goes into Pause mode and switchesoff. No measurement data from the buffer, log and memoryare lost.

3.4 Setting the Measurement Range

The measurement range is shown to the left and right of thequasi-analogue scale. Sound level meters without filter sets(Types 2236 A–009 and 2236 B–009) have 5 measurementranges, each with a dynamic range of 80 dB. Sound levelmeters with filter sets (Types 2236 C–009 and 2236 D–009)have an extra measurement range from 10 to 90 dB (you musthave one of the octave filters activated to select this range).

10 – 90 dB†

20 – 100 dB

30 – 110 dB

40 – 120 dB

50 – 130 dB

60 – 140 dB

* Baud rate and handshake are not affected† Only available with sound level meters with filter sets (Types 2236 C–009 and 2236

D–009) and when the filter is selected.

0

bb090913.book : 2236-ch3 Black 10

Chapter 3 – Setting Up the SLM for MeasurementSetting the Measurement Range


To move the measurement rangeby 10 dB, press Level ⟨⟩ or ⟨⟩,respectively.*

If you have selected a measurement range that is too low,the signal will cause an overload. If the sound level meter iscurrently overloaded, a + is shown to the right of the quasi-analogue scale. If the sound level meter has been overloadedduring a measurement since the last reset, OVL is shown atthe right-hand side of the screen, under the quasi-analoguescale.

* You can set the sound level meter to reset when changing the measurement range (see section 3.10).Then, if there are more than 1min of measurement results in the buffer (i.e. the elapsed time shownis greater than 1min), the screen tells you that changing the measurement range will erase all previousmeasurement results from the buffer.If you do not want to erase the measurement results, press ⟨ NO ⟩. The measurement range will notchange.Press ⟨ OK ⟩ to change the range and erase the measurement results.

931018/1e

Settings

Level

Frequency Wt. Parameter

0

Data• F• S• I

Brüel & Kjær Type 2236B K7/6-'89

Edit

NO

Show

OK

00:00:01F SPL 58.6 dBA

30 .... 110

bb090913.book : 2236-ch3 Black 11

Chapter 3 – Setting Up the SLM for MeasurementSetting the Time Weighting


3.5 Setting the Time Weighting

The time weightings available are shown below:

F: for normal measurementsS: for checking average levels of fluctuating noiseI: for measuring impulsive noise

The display shows N.A. if you select a time weighting whichis not available with the current displayed parameter.

* If there are more than 1min of measurement results in the buffer (i.e. the elapsed timeshown is greater than 1min), the screen tells you that changing the time weighting willerase all previous measurement results from the buffer.If you do not want to erase the measurement results, press ⟨ NO ⟩.Press ⟨ OK ⟩ to change the time weighting and erase the measurement results.

930499/1e

reset

reset

reset

*

*

*

·F·S·I

·F·S·I

·F·S·I

30 .... 110

PAUSE 00:00:00I SPL 58.6 dBA

30 .... 110

PAUSE 00:00:00S SPL 58.6 dBA

30 .... 110


931020/1e

Settings

Level


0

Data


Edit

NO

Show

OK


30 .... 110

• F• S• I

bb090913.book : 2236-ch3 Black 12

Chapter 3 – Setting Up the SLM for MeasurementSetting the Frequency Weighting


Note: If results are being logged every 0.1 s, the sound levelmeter sets the time weighting to 12 ms (shown on the displayby q). You cannot change the time weighting until you changethe logging rate or switch off auto logging (see section 3.11).

3.6 Setting the Frequency Weighting

3.6.1 Introduction

If the selected parameter is Peak or MaxP, then the frequencyweighting of the Peak signal is shown. Otherwise, the fre-quency weighting of the RMS signal is shown. Therefore, thefrequency weighting shown always corresponds to the select-ed parameter.

3.6.2 Setting the RMS Frequency Weighting

The available frequency weightings of the RMS signal areshown below:

A: for general sound level measurementsC: for checking the low-frequency content of a noise (if the

C-weighted level is much higher than the A-weightedlevel, then there is a large amount of low-frequencynoise)

L: for determining the “unweighted” SPLXHz: (with filters) for measuring the frequency content of a

noise in order to choose, for example, the relevanthearing protection

* If there are more than 1min of measurement results in the buffer (i.e. the elapsed timeshown is greater than 1min), the screen tells you that changing the frequency weightingwill erase all previous measurement results from the buffer.If you do not want to erase the measurement results, press ⟨ NO ⟩.Press ⟨ OK ⟩ to change the frequency weighting and erase the measurement results.

† Press Frequency Wt. ⟨ ⟩ to change the frequency weighting in the opposite direction toFrequency Wt. ⟨ ⟩.

bb090913.book : 2236-ch3 Black 13



* See footnote on previous page.† See footnote on previous page.

931516/1e

*†

*†

*†

*†

30 .... 110

PAUSE 00:00:00F SPL 58.6 dBL

30 .... 110

30 .... 110

PAUSE 00:00:00F SPL 58.6 dBC

30 .... 110


*†

*†

30 .... 110

PAUSE 00:00:00

30 .... 110

30 .... 110

PAUSE 00:00:00F SPL 58.6 dB

30 .... 110

PAUSE 00:00:0F SPL 58.6 dB

8kHz

Withfilter set

Withoutfilter set

4kHz

31.5Hz

F SPL 58.6 dB

Frequency Wt

Frequency Wt

Frequency Wt

Frequency Wt

Frequency Wt

Frequency Wt

931021/1e

Settings

Level


0

Data


Edit

NO

Show

OK


30 .... 110

• F• S• I

bb090913.book : 2236-ch3 Black 14



3.6.3 Setting the Peak Frequency Weighting

The available frequency weightings of the Peak signal areshown below:

C: for measuring the damaging effects of noise (inaccordance with the EU directive on exposure to noiseat work)

L: for special applications

* If there are more than 1min of measurement results in the buffer (i.e. the elapsed timeshown is greater than 1min), the screen tells you that changing the frequency weightingwill erase all previous measurement results from the buffer.If you do not want to erase the measurement results, press ⟨ NO ⟩.Press ⟨ OK ⟩ to change the frequency weighting and erase the measurement results.

931022e

Settings

Level


0

Data• F• S• I


PEAK WEIGHTING

NO

Edit

Show

OK

C

930724/2e

OK

reset

NO

3 x

Param.

OKShow

Edit*

30 .... 110

PAUSE 00:00:00F MaxP --·- dBC

PEAK WEIGHTING

C

PEAK WEIGHTING

C

L

C

NO

bb090913.book : 2236-ch3 Black 15

Chapter 3 – Setting Up the SLM for MeasurementSetting the Percentiles


3.7 Setting the Percentiles

Three LN parameters (percentile levels) are transferred overthe interface to a printer or computer (see sections 5.6 and5.7) with Overall Results. You can choose three percentilesor use the default percentiles L1, L10 and L90. The selectedpercentiles can also be displayed one after another on thedisplay (see section 4.8). N can have values of between 1 and99 in integer (1) steps.

Note:

Changing the percentiles does not reset the sound levelmeter. Therefore, you can view any percentile levels dur-ing or after a measurement.

The sound level meter always logs L10 and L90 in LoggedResults, regardless of the percentiles you have selected.

bb090913.book : 2236-ch3 Black 16

Chapter 3 – Setting Up the SLM for MeasurementSetting the Percentiles


931202/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

2:L103:L90

1:L1PERCENTILES

931087/2e

OKNO

8 x

Param.

OK

OKNO

OKNO

Show

Param.

Param.

Edit

30 .... 110

00:00:01F L50 46.5 dBA

PERCENTILES

2:L103:L90

1:L1

PERCENTILES

2:L103:L90

1:L1

PERCENTILES

2:L103:L90

1:L1

PERCENTILES

2:L103:L90

1:L1

Level

Level

PERCENTILES

99..21

99..21

99..21

NO

bb090913.book : 2236-ch3 Black 17

Chapter 3 – Setting Up the SLM for MeasurementSetting the Exposure Time


3.8 Setting the Exposure Time

Exposure Time is used in the calculation of LEP,d (see section8.2). It can have values of between 1min and 24hours.

Note: Changing the Exposure Time does not reset the soundlevel meter. Therefore, you can investigate the effect of dif-ferent Exposure Times on the LEP,d after a measurement.

931026/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

EXPOSURE TIME

7 30 hh:mm

(LEPd meas.)

OKNO Edit

9 x

Param.

OKShow

24*..

0100

30 .... 110

00:00:01F LEPd 46.5 dBA

EXPOSURE TIME

7:30 hh:mm

(LEPd meas.)

EXPOSURE TIME

7:30 hh:mm

(LEPd meas.)

931088/2e

Param.

59..

0100†

EXPOSURE TIME

7 30 hh:mm

(LEPd meas.)

OKNOLevel

OKNO

†00 not available if hh = 00*24 only available if mm = 00

NO

bb090913.book : 2236-ch3 Black 18

Chapter 3 – Setting Up the SLM for MeasurementSetting the Date and Time


3.9 Setting the Date and Time

The sound level meter’s clock operates, even when the soundlevel meter is switched off, if the internal back-up battery ischarged up (see section 3.2.3). It is factory set to CentralEuropean Time (CET).

931027/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

DATE/TIME

31 MAR 199309:30:00

930726/2e

Param.

Param.

OKNO

Edit

Level

OKNO

Level

OKShow4 x

30 .... 110


DATE/TIME

31 MAR 199309:30:00

DATE/TIME

31 MAR 199309:30:00

See next page

DATE/TIME

31 MAR 199309:30:00

31..21

Dec..

FebJan

NO

bb090913.book : 2236-ch3 Black 19

Chapter 3 – Setting Up the SLM for MeasurementSetting the Date and Time


OKNO

Level

Level

Param.

OKNO

Level

Param.

OK

Param.

NO

930700/1e

DATE/TIME

31 MAR 199309:30:00

DATE/TIME

31 MAR 199309 30:00

DATE/TIME

31 MAR 199309:30 00

See previous page

59..

0100

59..

0100

23..

0100

Level

Param.

OKNO

DATE/TIME

31 MAR 199309:30:00

2050..

19941993

bb090913.book : 2236-ch3 Black 20

Chapter 3 – Setting Up the SLM for MeasurementSetting the SLM to Change Range without Resetting


3.10 Setting the SLM to Change Rangewithout Resetting

The sound level meter always resets when changing the fre-quency or time weighting. The sound level meter also nor-mally resets when changing the measurement range.

As an option, you can set the sound level meter to changemeasurement range without resetting. If you do this andchange the range, the distributions and LN parameters arenot available (N.A. is shown on the display if an LN is se-lected). If the sound level meter is logging when you do this,then all LN values, including those already logged, will showN.A. To begin logging LN values again, reset the sound levelmeter by Pressing .0

931028e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

CHANGE RANGE

with reset

930727/2e

6 x

Param.

OK

OKNO

Show

Edit

30 .... 110


CHANGE RANGE

with reset

with reset

CHANGE RANGE

with

without

NO

bb090913.book : 2236-ch3 Black 21

Chapter 3 – Setting Up the SLM for MeasurementSetting up Auto Logging


Note:

If an overload has occurred, the results are not correct.You can, however, accept them (for example, if the over-load was of relatively short duration). If the sound levelmeter is set to not reset when changing the measurementrange, you will be unable to see from the Overall Resultsat which measurement range the overloads took place.You can, however, see when they took place in the LoggedResults (see sections 5.6 and 5.7 for how to view them).

The sound level meter takes 6 ms to change measurementrange. If you change range when the sound pressure levelis near its maximum and the sound level meter is set tonot reset when changing the measurement range, youwill reduce the accuracy of the measurement.

3.11 Setting up Auto Logging

You can set the sound level meter to automatically log:

Leq

L10

L90

measurement time of results

and store them at regular intervals in its log or send themvia the Serial Interface to a PC. The logging time (i.e. thetime between each set of results) can be one of the following:

0.1 s* 5 min

1 s 10 min

10 s 15 min

30 s 30 min

1 min 1hour

* Only Leq is logged. The sound level meter sets the time weighting to 12 ms (shown onthe display by q). You cannot change the time weighting. When the logging time is resetto any other value, or the autologging is switched off, the time weighting is restored toits previous setting.

bb090913.book : 2236-ch3 Black 22



If you change the range or the frequency or time weightingwhile the sound level meter is set to log results in the soundlevel meter’s memory, the sound level meter stops loggingand auto logging is set to Off. This is because the measure-ment set-up information in the log would no longer be rele-vant for further logged results.

931210/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

-every 1s (Leq L10 L90)

to logAUTO LOGGING

931089/2e

Param.

Param.

OK

OKNO

OKNO

Edit

Show

30 .... 110


AUTO LOGGINGOff

AUTO LOGGINGOff

AUTO LOGGINGto log–every 1s(Leq L10 L90)

Level*

* only available if not “Off”

1 hour..

1s0.1s

to interface

to log

Off

NO

bb090913.book : 2236-ch3 Black 23



If you change the auto logging status to log to the sound levelmeter’s memory, the sound level meter will, after a warning,erase any previously logged results.

Results are not logged while the sound level meter is in Pausemode. For more information about logging during pauses, seesection 5.8.

Pressing does not erase the log. To erase the log, seesection 5.3.

0

bb090913.book : 2236-ch3 Black 24

Chapter 3 – Setting Up the SLM for MeasurementSetting the Viewing Conditions


3.12 Setting the Viewing Conditions

The sound level meter’s screen can be changed to cope withvarious lighting, temperatures, conditions and viewing an-gles. You can switch on a back-light and adjust the screen’scontrast. The contrast adjustment may be especially usefulin very high or very low temperature environments.

To switch the back-light on, press .

The back-light switches off automatically 30s after the lastkey press. To switch the back-light off before this, press .

To set the screen’s contrast, follow the instructions below:

931031/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

CONTRAST

tTestTestTestTeTestTestTestTes

930800/2e

7 x

Param.

OKShow

30 .... 110

00:00:01F SPL 58.6 dBA

CONTRAST


CONTRAST


.

.

.

OKNO Edit

NO



Chapter 4

Measuring

4.1 Calibrating.............................................................................. 4 – 2

Introduction ....................................................................... 4 – 2Calibrating the Sound Level Meter.................................. 4 – 3Checking the Calibration .................................................. 4 – 5

4.2 Checking the Sound Level Meter................................. 4 – 7

4.3 Starting a New Measurement ...................................... 4 – 8

4.4 Pausing a Measurement ............................................... 4 – 10

4.5 Continuing a Measurement ......................................... 4 – 11

4.6 Starting a Frequency Analysis.................................... 4 – 12

4.7 Setting the SLM to Start Automatically ................ 4 – 13

4.8 Changing the Displayed Parameter ......................... 4 – 15


Chapter 4 – MeasuringCalibrating


4.1 Calibrating

4.1.1 Introduction

When to Calibrate

The standards recommend that you calibrate your sound levelmeter before each set of measurements (see section 4.1.2) andcheck the calibration after each set (see section 4.1.3).

Connecting a recommended microphone extension cable hasno effect on the sound level meter’s calibration. Therefore,you do not have to recalibrate after connecting one of therecommended microphone extension cables.

Principle of Calibration

The sound level meter uses a calibration factor to check fordrift. This is shown on the Calibration screen. When calibrat-ing, the sound level meter first checks the calibration signalagainst the calibration level you set. The sound level metershows you the factor required for correct calibration and asksif you want to recalibrate. If you press ⟨ OK ⟩, the sound levelmeter calibrates itself according to this new calibration level(i.e. it adjusts itself to the calibration level you entered).

During this procedure, the sound level meter is automaticallyset to use the reference measurement range and to show SPLon the display. The frequency and time weighting settingsare not changed. Therefore, calibration at frequencies otherthan 1 kHz requires correction for the frequency weightingused (see Fig. 6.1).

Calibrating for Free Field or Diffuse Field Measurements

The sound level meter is calibrated in the same way for freefield measurements (according to IEC) and diffuse field meas-urements (according to ANSI). However, the calibration levelsfor some calibrators may be different, depending on whichmeasurements are to be made. See the calibrator’s user man-ual for more details.




Always remove the Random Incidence Corrector DZ9566 (iffitted) from the microphone when calibrating or checking thecalibration.

Which Calibrators Can I Use?

The sound level meter can be calibrated with Sound LevelCalibrator Type 4231, Multifunction Acoustic Calibrator Type4226 or a similar calibrator. All are referred to on the soundlevel meter’s display as the calibrator.

Each calibrator is slightly different. The actual calibrationlevel is not necessarily equal to the nominal calibration level.It is, therefore, important to set the calibration level to theone given on the calibration chart for the calibrator used.

4.1.2 Calibrating the Sound Level Meter

Sound Level Calibrator Type 4231 provides a nominal pres-sure field calibration signal of 94 or 114 dB at 1 kHz. Thenominal diffuse field calibration signal is also 94 or 114 dBbut the nominal free field calibration signal is 93.8 or113.8 dB.

Multifunction Acoustic Calibrator Type 4226 provides a nom-inal calibration signal of 94, 104 or 114 dB at a range offrequencies.

For day to day calibration, you only need to calibrate at onelevel at one frequency. In order to comply with the standards,calibrate the sound level meter with a reference signal of94 dB at 1 kHz*.

* Calibration at frequencies other than 1kHz requires correction for the frequency weightingused (see Chapter 6). The sound level meter can correct up to ± 0.5 dB from the nominalcalibration level.




Fig.4.1 Fitting Sound Level Calibrator Type 4231 onto the sound levelmeter. Multifunction Acoustic Calibrator Type 4226 is fitted in asimilar way (see its manual)




To calibrate:

1. Fit the calibrator carefully onto the sound level meterand rest the sound level meter on a table or other flatsurface. Ensure that the calibrator fits snugly on themicrophone (see Fig. 4.1).

2. For the multifunction acoustic calibrator, set it up tocalibrate at 94dB and 1 kHz (see the calibrator’s instruc-tion manual).


The calibrator emits a 1 kHz calibration signal.

4. Follow the instructions given in the figure below to cal-ibrate to the relevant level for the type of measurementsto be made:*

4.1.3 Checking the Calibration

Follow the instructions given in section 4.1.2 until the soundlevel meter asks whether you want to recalibrate or not. Press⟨ NO ⟩ twice to return to the main screen.

* For Sound Level Calibrator Type 4231, choose a calibration level of 94 dB for diffusefield or 93.8 dB for free field. For Multifunction Acoustic Calibrator Type 4226, choose acalibration level of 94 dB for both diffuse and free field.




931032/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

CALIBRATION

94.0 dBCalibr. level:

2 x OKShow

Edit

30 .... 110

00:00:01F SPL 58.6 dBA

CALIBRATION

To calibratepress Edit

OKNO

Param.

OKNO

CALIBRATION

94.0 dBCalibr. level:

Factor: X.X dB

check cal.level

calibrate

930701/3e

New calibration

Use new factor?Factor: X.X dB

NO/OK

124.5:

123.5114.5

:113.594.5

:93.693.5

NO


Chapter 4 – MeasuringChecking the Sound Level Meter


4.2 Checking the Sound Level Meter

Before you start a longer series of measurements, it is goodpractice to check the status of the sound level meter’s battery,log and memory. To do this, press ⟨Edit ⟩ and ⟨OK ⟩. The soundlevel meter shows the status screen. Press ⟨OK ⟩ to return tothe sound level meter’s main screen.

Battery:With fresh batteries, the status screen will show approxi-mately 6V. When there is about half an hour’s operation left(when there is approximately 4 V), the battery voltage levelflashes (“3.9 V” will flash in the example shown in Fig. 4.2)*;in very cold weather, much less than half an hour is left.Thelength of time fresh batteries last depends on the conditionsof use (temperature, use of the back-light, etc.). Fresh alkalinebatteries in a sound level meter without a filter set (Type2236 A–009 or 2236 B–009) will take over 12 hours to wearout. Those in a sound level meter with a filter set (Type2236 C–009 or 2236 D–009) will take over 10 hours to wearout.

Note: The battery voltage will normally be higher just afterthe sound level meter is switched on. Therefore, always waita minute or so before checking the battery status.

* The main screen also shows a battery low warning (see Fold Out).

Fig.4.2 The sound level meter’s status screen

930988/1e

STATUSBattery : 3.9 VFree log : 123h12Free Records: 36


Chapter 4 – MeasuringStarting a New Measurement


Free log:The hours and minutes left in the log at the current rate oflogging are shown*.

Free Records:The number of empty Records left in the memory is alsoshown.

4.3 Starting a New Measurement †

If there are more than 1min of measurement results inthe sound level meter’s buffer (i.e. the elapsed time shownon the screen is greater than 1min), the screen tells you

* Up to a maximum of 255h59.† If you are only interested in instantaneous parameters (e.g. Peak or SPL), you can miss

out steps 3 and 5.

1. Calibrate the sound level me-ter as described in section4.1.

2. Select a suitable measure-ment range.

This reduces the risk of youhaving to change the rangeduring a measurement in or-der to avoid Overloads. Over-loads reduce the validity ofyour results and changingthe measurement range maycause a reset.

3. Press .

931033/1e

Settings

Level


Data• F• S• I


Edit

NO

Show

OK

00:00:01F SPL 46.5 dBA

30 ..... 110

0

0


Chapter 4 – MeasuringStarting a New Measurement


that resetting will erase all previous measurement re-sults from the buffer. If this occurs, press ⟨ OK ⟩ to confirmthat you want to reset the sound level meter.

The results in the sound level meter’s display buffer areerased and the elapsed time is set to zero. The overloadhold is reset so that the sound level meter indicates thatthere have not been any overloads since the last reset.

Note: To erase all results in the Log, Memory and displaybuffer, press and ⟨ Data ⟩.

4. If you want to measure according to IEC standards (i.e.free field), simply point the sound level meter towardsthe sound source.

If you want to measure according to ANSI standards (i.e.diffuse field), fit the supplied Random Incidence CorrectorDZ9566 on the microphone. The direction of the soundlevel meter is unimportant. If, however, the sound fieldis free, measure with the sound level meter at an angleof between 70 and 80˚ to the sound source.

5. Press .

The sound level meter starts measuring with the selectedset-up.

Note:

When mounting the sound level meter on a tripod, posi-tion the tripod so that one of its legs points in the samedirection as the sound level meter. This will reduce therisk of damaging the microphone if the tripod is acciden-tally knocked over.

See section 1.3 for practical hints and information aboutmeasuring according to standards.

0

bb090913.book : 2236-ch4 Black 10

Chapter 4 – MeasuringPausing a Measurement


4.4 Pausing a Measurement

The Pause mode of the sound lev-el meter allows you to store re-sults in its memory or transferresults across the interface to aprinter or computer.

Press .

PAUSE is shown on the left-handside of the display. The clockstops counting the measurementtime. The display and quasi-ana-logue scale continue to show thecurrent status of the displayedparameter and input signal level,respectively. In Pause mode, how-ever, no results or overload indi-cations are added to the buffer orthe log. For more informationabout logging during pauses, seesection 5.8.

931034/1e

Settings

Level


Data• F• S• I


Edit

Show


30 .... 110

0

NO OK

bb090913.book : 2236-ch4 Black 11

Chapter 4 – MeasuringContinuing a Measurement


4.5 Continuing a Measurement

Press .

“PAUSE” disappears from thedisplay. The clock continuescounting the measurement timefrom the point at which itstopped. Results are added to thebuffer and, if selected, the log.For more information about log-ging during pauses, see section5.8.

931684/1e

Settings

Level


Data• F• S• I


Edit

Show

F SPL 66.5 dB

31.5Hz30 .... 110

00:06:00

NO OK

0

bb090913.book : 2236-ch4 Black 12

Chapter 4 – MeasuringStarting a Frequency Analysis


4.6 Starting a Frequency Analysis*

A frequency analysis is a series of measurements in variousfrequency bands. Each measurement is made as for a normalbroad-band measurement (see section 4.3).

6. Using Frequency Wt. ⟨ ⟩ or ⟨ ⟩ , change the frequencyweighting to the centre frequency of the band in whichyou want to continue the analysis.

The sound level meter resets. You are now ready to meas-ure in the next frequency band.

7. Repeat steps 3 to 6 for the other bands in which youwant to analyse.

* Only available with sound level meters with filter sets (Types 2236 C–009 and 2236D–009)

1. Using Frequency Wt. ⟨ ⟩ or⟨ ⟩, change the frequencyweighting to the centre fre-quency of the band in whichyou want to start the analysis(see section 3.6.2).

2. Press .

3. Press .

4. After you have completed themeasurement in that fre-quency band, press .

5. Store the Overall Results inthe Memory (see section 5.1).

931684/1e

Settings

Level


Data• F• S• I


Edit

Show

F SPL 66.5 dB

31.5Hz30 .... 110

00:06:00

NO OK

00

bb090913.book : 2236-ch4 Black 13

Chapter 4 – MeasuringSetting the SLM to Start Automatically


4.7 Setting the SLM to StartAutomatically

The sound level meter can be set to automatically start atany time and date within the next month (e.g. from 19th Mayto 18th June).

931036e

Settings

Level


Data• F• S• I


0

OK

Edit

Show

NO

AUTO START

Off

930731/2e

OKNO

5 x

Param.

OKShow

Edit

30 .... 110


AUTO STARTOff

AUTO STARTOff

Level*

See next page

* only available if "On"

On

Off

NO

bb090913.book : 2236-ch4 Black 14

Chapter 4 – MeasuringSetting the SLM to Start Automatically


930789/1e

OKNO

OKNO

Param.

Param.

AUTO START

–day 19 May

–day 19 May

–day 19 May

–time 12:00:00

On

AUTO START

–time 12:00:00

On

OKNO

Param.

AUTO START

–time 12 00:00

On

* only available if "On"

Level*

See previous page

Level

Level

31..

0201

23..

0100

59..

0201

bb090913.book : 2236-ch4 Black 15

Chapter 4 – MeasuringChanging the Displayed Parameter


Auto Start only works if the sound level meter is switchedoff at the set time. Then, at this time, the sound level meterwill switch on, reset and, after a pause of 5 seconds, startmeasuring with the set-up it had when it was switched off.

Once the sound level meter has started measuring with AutoStart, you can control it in the normal way. Measurementwill continue until it is switched off manually or the batteriesrun out. Logging will continue until the memory is full or thebatteries run out.

If the sound level meter is already switched on at the timeit has been set to automatically start measuring, Auto Startis cancelled and has no effect.

When the set Auto Start time has passed, Auto Start will beswitched off when you switch off the sound level meter (untilthen, it will appear as though it is set in the Auto Startscreen). This prevents the sound level meter from repeatingan automatic measurement every month.

Auto Start does not affect your use of the sound level meterwhile the sound level meter is switched on. Therefore, youcan set the sound level meter up to start measuring at aparticular time and date while measuring without affectingyour current measurement results.

4.8 Changing the DisplayedParameter

The parameters available are listed in section 1.2.1. The se-lected parameter and its level are shown at the bottom of thescreen. After a reset, “––.–” is shown for the level until afterthe first second after a Pause. This is because the level isnot yet available. The quasi-analogue scale always shows thecurrent RMS input signal level, regardless of the selectedparameter.

bb090913.book : 2236-ch4 Black 16

Chapter 4 – MeasuringChanging the Displayed Parameter


A DC level corresponding to the instantaneous RMS level isemitted from the DC Output socket at the base of the soundlevel meter for recording on a plotter. The signal emitted fromthe AC Output socket is unaffected by which parameter orfrequency weighting is selected. It is always the L-weightedoutput from the preamplifier and is for recording noise signalson tape, transferring signals to an analyser or listening tothe input on headphones.

To step forwards and backwardsthrough the available parame-ters, press Parameter ⟨ ⟩ or⟨ ⟩, respectively.

When a Peak parameter isshown, the frequency weightingshows the current weighting ofthe Peak signal. When an RMSparameter is shown, the frequen-cy weighting shows the currentweighting of the RMS signal.

The display shows N.A. if you se-lect a displayed parameter whichis not available with the currenttime weighting or after changingthe measurement range withoutresetting.

931037/1e

Settings

Level


0

Data


• F• S• I

NO

Edit

Show

OK

00:00:01F MaxP 65.6 dBC

30 .... 110



Chapter 5

Storing and Transferring Results

5.1 Storing Results in a Record ............................................ 5 – 3

5.2 Recalling Results from a Record .................................. 5 – 4

5.3 Erasing Results .................................................................... 5 – 5

5.4 Setting up the Interface ................................................... 5 – 6

5.5 Setting up the Output Formats .................................... 5 – 8

Introduction ....................................................................... 5 – 8Output Formats............................................................... 5 – 10Level Distribution ........................................................... 5 – 15Cumulative Distribution................................................. 5 – 16Checking and Changing the Output Formats ............... 5 – 17

5.6 Printing .................................................................................. 5 – 18

5.7 Transferring Results to a Computer ........................ 5 – 21

5.8 Interpreting the Log Times .......................................... 5 – 24


Chapter 5 – Storing and Transferring Results


5.9 Recording on a DAT-recorder ...................................... 5 – 25


Chapter 5 – Storing and Transferring ResultsStoring Results in a Record


5.1 Storing Results in a Record

Results in the buffer can be stored as one of 40 records inthe sound level meter’s memory. The results are stored in thefirst available record (that is, the first set of results in record1, the next set in record 2, etc.).

Example: If you have stored 4 records and then erased record2, the sound level meter will store the next set of results inrecord 2. The next set of results will then be stored in thefirst available record (that is, record 5).

930510/1e

OKNO Data2x

30 .... 110


STORE

–As Rec. No. XOverall Results

931038e

Settings

Level


0


• F• S• I

NO

Edit

Show

OK

Data

STORE

–As Rec. No. XOverall Results


Chapter 5 – Storing and Transferring ResultsRecalling Results from a Record


5.2 Recalling Results from a Record

Results in a record in the memory can be recalled to thesound level meter’s buffer. You can then look at that record’sOverall Results.

931039/1e

Settings

Level


0


• F• S• I

NO

Show

OK

Data

Edit

F MaxL 103.2 dBA 00:20:00

RECORD NO.1

930511/4e

3 x

Param.

OKDataNO

NO

NOOK

OK

Edit

*

Param.

* XX = Last Record in memory

30 .... 110


F MaxL 103.2 dBA 00:20:00

RECALL

–no.XXRecord

RECALL

–no.XXRecord

RECORD NO.1

XX...1

Leq..

MaxPPeak


Chapter 5 – Storing and Transferring ResultsErasing Results


5.3 Erasing Results

You can erase results from a single record, all records (thatis, the entire memory) or the log.

931040/1e

Settings

Level


0


• F• S• I

NO

Show

OK

Data

Edit

–no. 1RecordERASE

930512/3e

Param.

Param.

OKDataNO 4x

OKNO

OKNO

Edit

†

Level*

* only available when Record selected† XX = last Record in memory

30 .... 110


–no. XXRecordERASE



Logged Results

All Records

Record

XX...1


Chapter 5 – Storing and Transferring ResultsSetting up the Interface


5.4 Setting up the Interface

The interfaces of the sound level meter and the instrument(for example, a printer or computer) it is connected to via theSerial Interface socket must have the same set-up to enablethem to communicate without losing or corrupting data.

Both the handshake and the baud rate of the sound levelmeter’s interface can be set.

The following types of handshake are available:

hardwire

XON/XOFF

none

The following baud rates are available:

1200

2400

4800

9600

19200


Chapter 5 – Storing and Transferring ResultsSetting up the Interface


931041/1e

Settings

Level


0


• F• S• I

NO OK

Data

Edit

Show

INTERFACE– 9600 Baud– XON/XOFF

931090/2e

10 x

Param.

OKShow

Edit

30 .... 110

00:00:01F SPL 58.6 dBA

XON/XOFF

Hardwire

No handshake

INTERFACE– 9600 Baud

INTERFACE

INTERFACE

OKNO

OKNO

Level

– XON/XOFF

– 9600 Baud

– XON/XOFF

– 9600 Baud– XON/XOFF

19200..

24001200

Param.

NO


Chapter 5 – Storing and Transferring ResultsSetting up the Output Formats


5.5 Setting up the Output Formats

5.5.1 Introduction

The output formats determine how the results are transferredto a printer or computer. Each type of result has its ownindependent output format.

Results

The following results are available with both long and shortheadings:

Overall Results (see section 1.2.4)

Logged Results (see section 1.2.4)

Level Distribution

Cumulative Distribution

Short Heading

Displays the set-up of the sound level meter in a short formattogether with the date and time of the start of the measure-ment (for overall results or distributions) or of the first log-ging (for logged results). See Fig. 5.2 to Fig. 5.8 for examplesof output formats with short headings.




Long Heading

A heading with space for remarksabout the measurement togetherwith the set-up of the sound levelmeter in a long format and thedate and time of the start of themeasurement (for overall resultsor distributions) or of the first log-ging (for logged results). SeeFig. 5.1 for an example of an out-put with a long heading (OverallResults).

Note: The long heading inspreadsheet format (see section5.5.2) is the same as the shortheading and is not as describedabove.

Fig.5.1 Overall Results outputformat with a long head-ing

bb090913.book : 2236-ch5 Black 10



5.5.2 Output Formats

You can print your logged results in any of the three formatsdescribed in this section. The format you choose will dependon the type of printer you are using.

Printer

For use with an IBM® Proprinter or compatible serial printer(for example, Serial Printer WQ 1138). The format is shownin Figs. 5.2 and 5.3.

Fig.5.2 Printer output formatwith short heading (re-sults logged every 1s)

Fig.5.3 Printer output formatwith short heading (re-sults logged every 0.1s)

bb090913.book : 2236-ch5 Black 11



“P” indicates that there has been a pause during that logginginterval (see section 5.8).

“O” indicates that there has been an overload (OVL) duringthe logging interval.

Printer (24 character/line)

You must use this format when you use Graphics PrinterType 2318. It uses a special character set (also for overallresults). Do not use this format with any other type of printer.



“&” indicates that there has been both a pause and an over-load (OVL) during the logging interval.

Printer (24 character/line) output format when results havebeen logged every 0.1s is the same as the Printer outputformat (see Fig. 5.3).

bb090913.book : 2236-ch5 Black 12



Fig.5.4 Printer (24 character/line) output format withshort heading (resultslogged every 1s)

bb090913.book : 2236-ch5 Black 13



Spreadsheet

A comma-delimited format (i.e. all text is in inverted commas(”) and data are separated by commas) for use with spread-sheet programs (e.g. Excel).



Fig.5.5 Spreadsheet output format (results logged every 1s)

bb090913.book : 2236-ch5 Black 14



Fig.5.6 Spreadsheet output format (results logged every 0.1s)

bb090913.book : 2236-ch5 Black 15



5.5.3 Level Distribution

Contains the following informa-tion:

The number of pauses

The percentage of the meas-urement time during whichthe sound level meter wasoverloaded (OVL)

MaxP

Leq

The level distribution (i.e. thepercentage of the measure-ment time during which theSPL was within a certain dBrange)

If there has been an under-load, the percentage of themeasurement time duringwhich the sound level meterwas underloaded

All values are to one decimalplace.

Level distribution is availablewith 1 or 5 dB resolution.

Fig.5.7 Level Distribution outputformat with a shortheading

bb090913.book : 2236-ch5 Black 16



5.5.4 Cumulative Distribution

Contains the following informa-tion:

The number of pauses

The percentage of the meas-urement time during whichthe sound level meter wasoverloaded (OVL)

MaxP

Leq

The cumulative distribution(i.e. the percentage of themeasurement time duringwhich the SPL was over acertain dB level)

If there has been an under-load, the percentage of themeasurement time duringwhich the sound level meterwas underloaded

All values are to one decimalplace.

Cumulative distribution is avail-able with 1 or 5 dB resolution.

Fig.5.8 Cumulative Distributionoutput format with ashort heading

bb090913.book : 2236-ch5 Black 17



5.5.5 Checking and Changing the Output Formats

931042/1e

Settings

Level


0


• F• S• I

NO OK

Data

Edit

Show

-short heading-printer

Logged ResultsOUTPUT FORMATS

931091/2e

Param.

Param.

Param.

OK

NOOK

NOOK

long

short

Logged Res.Overall Res. Cum. Distr. Level Distr.

printer

Logged Results:

printer :24chrspreadsheet

5dB resolut.

1dB resolut.

Distribution:

Edit

Show

NOOK

* only available when Logged Results or Cumulative or Level Distribution selected

30 .... 110

00:00:01F SPL 58.6 dBA

OUTPUT FORMATS


Logged Results

OUTPUT FORMATS


Logged Results

Level

Level*

OUTPUT FORMATS


Logged Results

OUTPUT FORMATS


Logged Results

11 x

NO

bb090913.book : 2236-ch5 Black 18

Chapter 5 – Storing and Transferring ResultsPrinting


5.6 Printing

You can print results directly from the sound level meter byusing any of the following printers:

Portable Printer Type 2322

An IBM® Proprinter compatible serial printer

Graphics Printer Type 2318.

The baud rates (see section 5.4) of the sound level meter andthe printer must be the same to enable them to communicatewithout losing or corrupting data.

Warning! When connecting the sound level meter to a print-er, ensure that both the printer and the sound level meterare switched off. Otherwise the instruments could be dam-aged. Note that this does not apply to Portable Printer Type2322, since it does not have a power switch.

To print:

1. Connect the printer to the sound level meter via theSerial Interface socket on the base of the sound levelmeter. Use one of the following cables:

For Portable Printer Type 2322, use Interface CableAO 0532 (supplied with printer).

For serial printers with a 25-pole interface, use 9-pole Cable with 25-pole Adaptor AO 1386

For serial printers with a 9-pole interface, use 9-poleCable with 25-pole Adaptor AO 1386, but remove theadaptor.

For IBM® Proprinter compatible parallel printers,use Interface Module UL 0064.

For Graphics Printer Type 2318, use Interface CableAO 0404.

2. The communications settings (baud rate and handshake)on the sound level meter must match those of the printer.

bb090913.book : 2236-ch5 Black 19



If you are using Portable Printer Type 2322, then set the2236 to 9600 baud and XON/XOFF handshake (see sec-tion 5.4 for instructions). If you are using another printer,please refer to your printer manual for settings.

3. Set up the Output Format of the results you want toprint (see section 5.5). If you are using Portable PrinterType 2322 or an IBM® Proprinter compatible, select“Printer”. For printing on a Graphics Printer Type 2318,select “Printer (24 char./line)”.

4. Set the sound level meter in Pause mode and follow theinstructions given in the figure below.

The printer prints the selected results in the selected outputformat (see section 5.5).

To stop printing:

To stop printing at any time, press ⟨ NO ⟩. This will stopprinting immediately and delete all unprinted data from theprinter’s buffer.

bb090913.book : 2236-ch5 Black 20



931043/1e

Settings

Level


0


• F• S• I

NO OK

Edit

Show

Data

Overall ResultsPRINT

930516/2e

Param.

Param.

OKDataNO

OKNO

OKNO

Edit

†

All RecordsRecord

Level Distrib.

Overall Res.

Level*

30 .... 110





PRINTRecord-no.XX

XX..21

Logged Res.

Cum. Distrib.

bb090913.book : 2236-ch5 Black 21

Chapter 5 – Storing and Transferring ResultsTransferring Results to a Computer


Errors

If the printer does not print out, check:

The baud rates and handshake of the sound level meterand printer. If they are not the same, switch the printeroff, correct the sound level meter’s baud rate and/or hand-shake (see section 5.4) so that they are the same as theprinter’s and switch the printer on again (some printersonly check the interface while switching on)

The interface cable between the sound level meter andthe printer

If neither of these steps work, consult your local Brüel&Kjærservice representative.

5.7 Transferring Results to aComputer

You can also control the sound level meter from a computer(see section 8.3).

Warning! When connecting the sound level meter to thecomputer, ensure that both the computer and the sound levelmeter are switched off. Otherwise the instruments could bedamaged.

To transfer:

1. Connect the computer to the sound level meter via theSerial Interface socket on the base of the sound levelmeter using 9-pole Cable with 25-pole Adaptor AO 1386.If the computer has a 9-pole interface socket, remove theadaptor.

2. Start a communications program (e.g. BK–Link, Pro-Comm, or Brüel & Kjær Reporter or Brüel & Kjær dB2XL)on the computer. If you are using Reporter or dB2XL,then please refer to your Reporter or dB2XL documenta-tion for more information.

bb090913.book : 2236-ch5 Black 22



3. Configure the computer as follows:

9600 Baud8 data bits1 stop bitParity: noneHandshake: XON/XOFF

4. On the computer, enter the name of the file to which youwant the results to be transferred (see the instructionmanual for the communications program).

5. Set the sound level meter’s baud rate to 9600 and itshandshake to XON/XOFF (see section 5.4).

The baud rates and handshake of the sound level meterand the computer must be the same to enable them tocommunicate without losing or corrupting data.

6. Set up the Output Format of the results you want totransfer (see section 5.5). If you are using Reporter ordB2XL, or will be using the Logged Results in a spread-sheet program, select the Spreadsheet format.

7. Set the sound level meter in Pause mode and follow theinstructions given in the figure below.

bb090913.book : 2236-ch5 Black 23



931043/1e

Settings

Level


0


• F• S• I

NO OK

Edit

Show

Data

Overall ResultsPRINT

930516/2e

Param.

Param.

OKDataNO

OKNO

OKNO

Edit

†

All RecordsRecord

Level Distrib.

Overall Res.

Level*

30 .... 110





PRINTRecord-no.XX

XX..21

Logged Res.

Cum. Distrib.

bb090913.book : 2236-ch5 Black 24

Chapter 5 – Storing and Transferring ResultsInterpreting the Log Times


The results are transferred to the computer under the nameyou have chosen from the computer program.

If you have used a standard communications program tosave the data as a spreadsheet file, then you can importthe results into a spreadsheet program (e.g. MicrosoftExcel).

If you are using Brüel & Kjær Reporter software, then thedata will be displayed in Reporter.

If you are using Brüel & Kjær dB2XL, then the data willautomatically be displayed in Microsoft Excel.

Errors

If the results are not transferred, check:

The baud rates and handshake of the sound level meterand computer. If they are not the same for both, changethe configuration of the computer so that the settingsmatch those for the sound level meter.

Which port is used on the computer.

The interface cable between the sound level meter andthe computer.

If none of these steps work, consult your local Brüel&Kjærservice representative.

5.8 Interpreting the Log Times

When logged data is displayed, each log is tagged with thetime the measurement was taken. Sometimes, you may pausemeasurement while logging readings, which may cause someconfusion when interpreting your log. This section gives ex-amples that show how to interpret your time readings.

Assume that the sound level meter is set to log at regularintervals of 10 seconds. The times attached to the logged datause the following rules:

In the print-out, the times always refer to the start of ameasurement period.

bb090913.book : 2236-ch5 Black 25

Chapter 5 – Storing and Transferring ResultsRecording on a DAT-recorder


When a pause is activated (for example, 3 seconds aftera measurement period has started) the measurement willimmediately stop. When pause is deactivated, the meas-urement will continue and ends when a total of 10 sec-onds has expired (7 seconds later). This is independentof the duration of the pause. The measurement periodtherefore has been broken into two parts with a pausein between (see Fig. 5.9).

Time periods in which a pause has occurred will bemarked with a P in the print-out. For example, the meas-urement marked :22P in Fig. 5.9.

5.9 Recording on a DAT-recorder

Recording signals on a DAT-recorder via the sound level meteris useful for getting a calibrated recording for full analysisof impulsive noise or for examining the noise for pure tones.Also, later on, you can listen to the signal in order to be ableto identify certain events such as a barking dog or slammingdoor.

To record:

1. Connect the DAT recorder to the sound level meter viathe AC Out socket on the base of the sound level meterusing LEMO to BNC Cable AO0403.

An adaptor may be required for the input sockets ofcertain DAT-recorders.

2. Set the maximum input of the DAT-recorder to at least500mVrms.

Fig.5.9 An example of logging times with pause intervals

960554e

10

:12 :22P :57 :07 :17

3 7 10

25 s Pause

10 10

Logging Time Stamps

Seconds

bb090913.book : 2236-ch5 Black 26

Chapter 5 – Storing and Transferring ResultsRecording on a DAT-recorder


3. Set the sound level meter to a suitable range (one thatcovers the sound levels and does not cause overloads).

It is important to do this to ensure that you know whatrange the recorded signal represents.

4. Start recording.

5. Record the calibration signal from the calibrator.

This will allow you to accurately adjust the sensitivity ofthe analysis equipment on playback.

6. Measure.

7. After measuring, record the calibration signal again.

8. Stop recording and switch the sound level meter off.

For more information on recording using a DAT-recorder, seethe recorder’s manual.

Errors

If the DAT-recorder does not record, check:

The cable between the sound level meter and the DAT-recorder

The DAT-recorder

If neither of these steps works, consult your local Brüel&Kjærservice representative.



Chapter 6

Specifications

6.1 Specifications......................................................................... 6 – 2

6.2 Ordering Information ...................................................... 6 – 10


Chapter 6 – SpecificationsSpecifications


Fig.6.1 Nominal frequency weighting characteristics

10 100 1k 10k

0

–10

–5

–1520 50 200 500 2k 5k 20k 50k5

2

(dB)

Relative Response

930733/1eFrequency (Hz)

C

L

C

L

A

Noise Floor:Under reference conditions:

At 40°C and 95% RH, add 2 dB to typical valuesand 3 dB to maximum values.Includes preamplifier’s electrical noise and micro-phone’s thermal noise.

Parameters:MaxL, MinL, MaxP, Peak, SPL, Leq, LIm, SEL, IEL,LEP,d, LN (3 values with L90, L10 and L1 as default)and Overload in % of measurement timeResolution:

LN Values: 0.5 dBOther Parameters: 0.1 dB

Frequency Weighting

A C Lin

Typical Noise Floor 17 18 23

Max. Noise Floor 20 20 26

Level at which noisefloor causes a non-lin-earity of < 0.4 dB

30 30 36

Level at which noisefloor causes a non-lin-earity of < 1 dB

26 26 32

6.1 Specifications

Standards:Conforms with IEC 651 (1979) and IEC 804 (1985)Type 1, and IEC 1672 (Draft, June 1996) Class1. Conforms with ANSI S1.4 – 1983 and DraftS1.43, 6th September, 1992 Type 1I. Conformswith BS 5969 and BS 6698 Type 1 I.

1/1-octave filter set conforms with IEC 1260 – 1995,Class 1; ANSI S1.11–86, order 3, Type 1–D; andBS 2475 (1964). (Types 2236 C and 2236 D only)

Measuring Ranges:

* Only available with Types 2236 C–009 and 2236 D–009when filter selected.

† For linearity range specifications, see the table givenunder Noise Floor.

Range(dB)

Max.Peaklevel

Upper limit (RMS) forsignals with crestfactor = 10 (20 dB)

10* – 90 93 73

20† – 100 103 83

30 – 110 113 93

40 – 120 123 103

50 – 130 133 113

60 – 140 143 123




Fig.6.3 1/1-octave filter characteristics as a function of frequency, f, against centre fre-quency, fm (detail of Fig.6.2). IEC tolerances are shown as dashed lines

1

0

–2

–4

0.5 2

Relative response (dB)

932123/1e

1.50.90.80.70.6

1

–1

–3

–5f/fm

Fig.6.2 1/1-octave filter characteristics as a function of frequency, f, against centre fre-quency, fm. IEC tolerances are shown as dashed lines

1 10

10

0

–10

–20

–30

–40

–50

–60

–70

–800.5 2 20 500.05 3 300.250.125 84


f/fm932122/1e




Fig.6.4 Response of the sound level meter to tone bursts of varying characteristics

1 10

0

–10

– 20

– 30100

nominal

I F

measured

Pulse length (ms) t

Reading in dB referred to continuous signal level (dB)

931682e

t

4 kHz

S

Frequency Weighting:Selected independently for RMS and PeakRMS:A, C according to BS5969 Type 1L: As shown in Fig.6.1 with Type 1 tolerancesPeak:C according to BS5969 Type 1L: As shown in Fig.6.1 with Type 1 tolerancesFilter*:Band-pass Filters: Nine 1/1-octave filters at 1/1-octave intervals (base 10)Centre Frequencies: 31.5, 63, 125, 250, 500Hz,1, 2, 4, 8kHzCharacteristics: As shown in Figs. 6.2 and 6.3

Detectors:Simultaneous RMS and Peak with independentfrequency weightingsLinearity Range: 80dBPulse Range: 83dBNon-linear Distortion: Too small to affect accu-racyPeak Detector Rise Time: Typically 50µs

Time Weighting:S, F, I according to BS5969 Type 1 (typically betterthan Type 0). See Fig.6.4When Logging Every 0.1 s: 12 ms (indicated onthe display by q)

Display:4 line LCD showing:

Measuring range and quasi-analogue barshowing input signal

* Only available with Types 2236 C–009 and 2236 D–009when filter selected.

Battery low, pause and overload with hold in-dicators

Time weighting and elapsed measurement time Frequency weighting (Peak or RMS) or filter

centre frequency†, selected parameter with lev-el

Back-light with switchThe quasi-analogue bar is updated 10 times persecondDisplayed parameter level updated once per sec-ond

Exchange Rate:3dB

Reset:Resets Buffer (including elapsed time) to zeroWarning prior to reset if elapsed time > 1minReset when changing frequency or time weightingResets all results in Log, Memory and Buffer ifheld down together with ⟨ Data ⟩Optional reset when changing level of measure-ment range (LNs and distributions not available ifrange change is without reset)

Memory:40 Records of Overall Results

Result Logging:Leq, L10 and L90Logged Every: 0.1‡, 1, 10, 30s, 1, 5, 10, 15,30min or 1hour

† Only available with Types 2236 C–009 and 2236 D–009when filter selected.

‡ Only Leq logged at this setting




Logged To: log or interfaceMemory Capacity: 128KBytes (Types 2236A–009 and 2236 C–009). Equivalent to 21600sets of results (for example, 6h of 1s logging).512KBytes (Types 2236 B–009 and 2236 D–009).Equivalent to 86400 sets of results (for example,24h of 1s logging)

Microphone:Type 4188 Prepolarized Free-field 1/2″ CondenserMicrophoneSensitivity: –30 dB re 1V/Pa ±2 dBFrequency Range: 8Hz to 12.5 kHz ±2 dBCapacitance: 12pF

Serial Interface:Compatible with EIA–574Compatible with EIA–232–E with 25-pole adaptorBaud Rate: 1200 – 19200Data Bits: 8Stop Bit: 1Parity: NoneHandshake: Hardwire, XON/XOFF or NoneResult Output Formats:Overall and Logged Results, Level and Cumula-tive DistributionHeading: Long or shortOutput Format Types: Printer, Printer (24 char./line) or SpreadsheetDistribution Resolution: 1 or 5 dB

DC Output:Short-circuit protected coaxial socket (LEMO se-ries 00)Output: 50mV/dB equivalent to 0 – 4 VOutput Resistance: 100 ΩOutput: Sampled detector outputUpdated: 160 times per second

AC Output:Short-circuit protected coaxial socket (LEMO se-ries 00)Output: 0.5V RMS corresponding to the top ofthe selected measurement range ±2 dB dependingon the microphone’s sensitivityOutput Resistance: 100 ΩSignal: Output signal from preamplifier (L frequen-cy weighting)

Clock:Real-time (calendar) and measurement durationFactory set to CET

Warm-up Time:Less than 5s

Effect of Magnetic Field80A/m (1Ørsted) at 50 Hz gives <34 dB (L)

Calibration Conditions:Reference Frequency: 1000 HzReference SPL: 94dBReference Temperature: 20°C (68°F)Reference RH: 65%Reference Range: 50 – 130 dB (set automaticallyduring calibration sequence)Reference Direction of Incidence: FrontalCalibration Correction with Extension Cable:0 dB

Environmental Effects:Storage Temperature: –25 to +70°C (–13 to+158°F)Operating Temperature: –10 to +50°C (14 to122°F)Effect of Temperature: <0.5 dB (–10 to +50°C)Effect of Humidity: <0.5 dB for 30%<RH<90%(at 40°C, 1 kHz)

Vibration Sensitivity<80 dB with L-weighting at 1m/s–2 horizontally<85 dB with L-weighting at 1m/s–2 vertically

Batteries:Four 1.5 V LR6/AA size alkaline cellsLifetime (at room temperature):Typically > 12h for Types 2236 A–009 and2236 B–009.Typically > 10h for Types 2236 C–009 and2236 D–009Internal back-up battery:Keeps clock and memories operating for 6months(typically) if fully charged.

External Power Supply:Must fulfil the following specificationsVoltage: regulated or smoothed 7–15V DCVoltage Ripple: <100mV peak to peakMaximum Current: 400 mAAverage Current: ~100 mA at 7 VSocket:

Centre Pin: PositiveCasing: NegativePin Diameter: 2.0mmExternal Diameter: 5.5mm

Physical Characteristics:Size: 257×97×41mmWeight: 460g (incl. batteries)




CE-mark indicates compliance with EMC Directive

Safety EN 61010–1 (1993) and IEC 1010–1 (1990): Safety requirements for electricalequipment for measurement, control and laboratory use

EMC Emission EN 50081–1 (1992): Generic emission standard. Part 1: Residential,commercial and light industryEN 50081–2 (1993): Generic emission standard. Part 2: Industrial environmentCISPR 22 (1993): Radio disturbance characteristics of information technologyequipment. Class B LimitsFCC Rules, Part 15: Complies with the limits for a Class B digital device

EMC Immunity EN 50082–1 (1992): Generic immunity standard. Part 1: Residential,commercial and light industryRF immunity implies that sound level indications of 45dB or greater will beaffected by no more than ±0.5 dBEN 50082–2 (1995): Generic immunity standard. Part 2: Industrial environmentRF immunity implies that sound level indications of 60dB (see note, below) orgreater will be affected by no more than ±0.5 dB

Note:RF immunity is 14 dB better than the requirements given in IEC 1672 (Draft, June 1996) Class 1.




Frequency Response

Fig.6.5 Typical free-field response of Microphone Type 4188 for 0 ° incidence withoutrandom incidence corrector

Fig.6.6 Typical diffuse-field response of Microphone Type 4188 with random incidencecorrector

931262/1e

-3

-2

-1

0

1

2

3

10 20 50 100 200 500 1k 2k 5k 10k 20k

Tol.

Tol.Tol.

Tol.

Frequency response satisfies IEC 651 Type 1


Frequency (Hz)

931263/1e

-3

-2

-1

0

1

2

3

10 20 50 100 200 500 1k 2k 5k 10k 20k

Frequency response satisfies ANSI S 1.4–1984 Type 1


Frequency (Hz)




Directional Characteristics:

Fig.6.7 Directional characteristics of the complete instrument at 1, 2, 4, 8, 12.5 kHz

931238/1e

Brüel & Kjær

0°

330°

300°

270°

240°

210°

180°

150°

120°

90°

60°

30°

4050 30 20 10 0 50403020100

QP

5102

Brüel&Kjær

QP

5102

Brüel & Kjær

0°

330°

300°

270°

240°

210°

180°

150°

120°

90°

60°

30°

4050 30 20 10 0 50403020100

QP

5102

Brüel&Kjær

QP

5102

12.5kHz

Brüel & Kjær

0°

330°

300°

270°

240°

210°

180°

150°

120°

90°

60°

30°

4050 30 20 10 0 50403020100

QP

5102

Brüel&Kjær

QP

5102

8 kHz

Brüel & Kjær

0°

330°

300°

270°

240°

210°

180°

150°

120°

90°

60°

30°

4050 30 20 10 0 50403020100

QP

5102

Brüel&Kjær

QP

5102

4 kHz

2 kHz

Brüel & Kjær

0°

330°

300°

270°

240°

210°

180°

150°

120°

90°

60°

30°

4050 30 20 10 0 50403020100

QP

5102

Brüel&Kjær

QP

5102

1 kHz

0

Brüel & KjærType 2236 BK 7/6-'89

OVL 02:00:00F MaxL 83·6 dBA

40 .... 120+

5dB




Effect of Accessories

Fig.6.8 (a) Effect of the sound level meter’s casing on its frequency response (for refer-ence) compared to (b) the effect of Tripod UA 0801 on the sound level meter’sfrequency response

Fig.6.9 Effect of Protective Cover UA 1236 on the sound level meter’s frequency re-sponse

931236/1e

RelativeResponse

(dB)

(a)

100 1k 10k

0

– 1200 500 2k 5k 20k

1

Frequency (Hz)

100 1k 10k

0

– 1200 500 2k 5k 20k

1

931235/1eFrequency (Hz)

RelativeResponse

(dB)

(b)

931234/1e

RelativeResponse

(dB)

100 1k 10k

0

– 1200 500 2k 5k 20k

1

Frequency (Hz)

bb090913.book : 2236-ch6 Black 10

Chapter 6 – SpecificationsOrdering Information


6.2 Ordering Information

Type 2236 A Precision Integrating SoundLevel Meter

Type 2236 B Precision Integrating SoundLevel Meter (extended memory)

Type 2236 C Precision Integrating SoundLevel Meter with 1/1 -octave filterset

Type 2236 D Precision Integrating SoundLevel Meter with 1/1 -octave filterset (extended memory)

Includes the following accessories:

Type 4188: Prepolarized Condenser Micro-phone Cartridge

KE 0323: Shoulder BagUA 1236: Protective Cover4 ×QB 0013 Four 1.5 V LR6/AA size alkaline

cells

Optional Accessories:Type 4231: Sound Level CalibratorType 4226: Multifunction Acoustic Calibra-

torType 7694 Reporter SoftwareType 7692 dB2XL Communication Macro

for Microsoft Excel™Type 2322 Portable Printer (includes con-

nector cable AO 0532)UA 1251: TripodUA 0801: TripodUA 1254: Microphone Holder (for tripod)UA 0237: Windscreen (∅ 90 mm)UA 0459: Windscreen (∅ 65 mm)AO 0408: Microphone Extension Cable

(3 m)AO 0409: Microphone Extension Cable

(10 m)AO 0403 LEMO to BNC CableAO 1386 9-pole Cable with 25-pole Adap-

tor (for computer and serialprinter)

UL 0064 Interface ModuleZG 0386 Power Supply for EuropeZG 0387 Power Supply for UKZG 0388 Power Supply for USA

Upgrades:

ZT0326 Octave Filter Set

Carrying Cases:

KE 0325: Carrying Case with insert forsound level meter, Sound LevelCalibrator Type 4231 and TripodUA 1251

Brüel&Kjær reserves the right to change specifi-cations and accessories without notice.



Chapter 7

Service and Repair


Chapter 7 – Service and Repair


Precision Integrating Sound Level Meter Type 2236 is de-signed and constructed to provide many years of reliableoperation. However, if a fault occurs which impairs the soundlevel meter’s correct function, then remove its main batteriesand disconnect any external power supply to prevent risk offurther damage.

For repair, contact your local Brüel&Kjær service represent-ative.



Chapter 8

Appendices

8.1 SEL............................................................................................. 8 – 2

8.2 LEP,d .......................................................................................... 8 – 3

8.3 Controlling the Sound Level Meterfrom a Computer.................................................................. 8 – 4

Introduction ....................................................................... 8 – 4Commands ......................................................................... 8 – 6


Chapter 8 – AppendicesSEL


8.1 SEL

SEL (the Sound Exposure Level) is the constant sound levelwhich, if maintained over 1s, would have the same energyas the measured Leq over the measurement time, T (seeFig. 8.1).

If the time weighting is I, SEL becomes IEL.

Fig.8.1 SEL compared to weighted Leq

831794/1eSound Pressure Level (dB)

Time-varying RMS

Measurement duration

SEL

1 s

Leq

Time (s)


Chapter 8 – AppendicesLEP,d


8.2 LEP,d

LEP,d (the Daily Personal Noise Exposure Level) is the con-stant sound level which, if maintained over 8 hours, wouldhave the same energy as the measured A-weighted Leq ex-tended over the Exposure Time, Te (see Fig. 8.2).

In Fig. 8.2:

LAeq = the average level during the Exposure Time

T = the actual measurement time

Te = The Exposure Time

The Exposure Time can be set using the sound level meter’sSettings (see section 3.8). Therefore, you can investigate theeffect of different Exposure Times on the LEP,d.

Fig.8.2 LEP,d compared to LAeq

913275/1e

8h

L

EP,d

t

L

T

AeqL

Te


Chapter 8 – AppendicesControlling the Sound Level Meter from a Computer


8.3 Controlling the Sound LevelMeter from a Computer

8.3.1 Introduction

Messages From the Sound Level Meter

This chapter describes the operation of the sound level metervia its serial interface. It assumes that you are familiar withmanual operation of the sound level meter and have someexperience of interface programming.

Command Syntax

All commands can be truncated to a mnemonic indicated bycapitals in the section title:

e.g. AUTOLog can be written as AUTOL

If a command is unknown, the sound level meter sends thefollowing message:

UNKNOWN COMMAND

If a parameter following a command is unknown, the soundlevel meter normally treats the command message as a querymessage. In some cases, the sound level meter sends an ex-planatory message instead.

All messages sent to the sound level meter must end with⟨ Return ⟩.

All messages from the sound level meter end with ⟨ CR ⟩ and⟨ LF ⟩ (carriage return and line feed).

Note: In the syntax diagrams in section 8.3.2, SP represents⟨ Space bar ⟩ and CR represents ⟨ CR ⟩ and ⟨ LF ⟩ (carriagereturn and line feed).

Setting up the Computer

Warning! When connecting the sound level meter to thecomputer, ensure that both the computer and the sound level




meter are switched off. Otherwise the instruments could bedamaged.

1. Connect the computer to the sound level meter via theSerial Interface socket on the base of the sound levelmeter using 9-pole Cable with 25-pole Adaptor AO1386.If the hrscomputer has a 9-pole interface socket, removethe adaptor.

2. Start a communications program (e.g. BK–Link or Pro-Comm) on the computer. Alternatively, use Brüel & Kjærsoftware such as Reproter or dB2XL, which are writtenspecifically for communicating with your sound level me-ter and working with and displaying sound level meterdata.

3. Configure the computer as follows:

9600 Baud8 data bits1 stop bitParity: noneHandshake: XON/XOFF (see section 5.4)

4. Switch on the sound level meter.

5. Set the sound level meter’s handshake to XON/XOFF andits baud rate to 9600 (see section 5.4).

6. Press ⟨ Enter ⟩ on the computer.

Communication is established and the prompt (> ) isshown on the computer screen. The sound level metercan now be controlled from the computer.

Note: The baud rates and handshake of the sound level meterand the computer must be the same to enable them to com-municate without losing or corrupting data.




8.3.2 Commands

There are two types of commands:

Commands: Change the set-up of the sound level meteror order it to do something.

Queries: Cause the sound level meter to display infor-mation about its setup.

The command and query messages available are listed inTable 8.1.

Message Command Query Message Command Query

AUTOLog • • FW • •

AUTOStart • • HAndshake • •

BATt • OFf •

BAUd • • PAuse •

CLock • • PErcentile • •

CONtinue • PRint •

DEFault • PW • •

DISp • • RANge • •

ELapsed • RESet •

ERASE • SETup •

EXPosure • • STOre •

FOrmat • • TW • •

FREE • VErsion •

Table 8.1 Command and query message overview




AUTOLog

The AUTOLog command message sets the destination of thedata and rate of logging. The query message shows the cur-rent status. When logging data over the interface, the soundlevel meter cannot be controlled from the computer except tochange the status of the auto logging. Changing the rate oflogging data resets the sound level meter. The data fields andtheir settings are listed in Table 8.1.

Field Name Field Setting Comments

Status (command) ILO

To interfaceTo internal logOff

Rate 0.1*1 s10 s30 s1 m5 m10 m15 m30 m1 h

0.1s, Leq only

1minute

1hour

Status (response) INTERFACELOGOFF

* Causes TW Status to be set to Q. TW Status cannot be changed while AUTOLog Rate is 0.1 andStatus is not Off

Table 8.2 AUTOLog data fields and codes




Fig.8.3 Syntax for the AUTOLog command

Fig.8.4 Syntax for the AUTOLog query message and sound level meterresponse

930664e

To Sound Level Meter

StatusSPAUTOLOG — SP—

Rate

930665e


AUTOLOG

From Sound Level Meter

StatusCRMEASUREMENTS RESET AUTOLOGGING:— SP—SP—

Rate




AUTOStart

The AUTOStart command message sets the auto start time,day of the month and status. The query message shows thecurrent auto start status. The data fields and their settingsare listed in Table 8.3.

Fig.8.5 Syntax for the AUTOStart command

Fig.8.6 Syntax for the AUTOStart query message and sound level meterresponse


Date DD Up to 1 month ahead

Time HH:MM:SS

Status ONOFF

Table 8.3 AUTOStart data fields and codes

930662e


DateSPAUTOSTART — SP—

Time StatusSP—

930663/1e


AUTOSTART


DateSPAUTOSTART: — SP—

Time StatusSP—

bb090913.book : 2236-ch8 Black 10



BATt

The BATt query message shows the current voltage level andstatus of the battery. Together with the FREE command, itis equivalent to the Status Fast Edit function available fromthe front plate of the sound level meter. The data fields andtheir settings are listed in Table 8.4.

BAUd

The BAUd command message sets the sound level meter’sbaud rate. After you have changed the sound level meter’sbaud rate, you must change the computer’s baud rate to thesame value in order to continue communicating with thesound level meter.

Fig.8.7 Syntax for the BATt query message and sound level meter re-sponse


Level XX.X Volts

Status LOW Replace batteries

Table 8.4 BATt data fields and codes

930666e


BATT


LevelSPBATTERY VOLTAGE: VOLTS— SP—

StatusSP —

bb090913.book : 2236-ch8 Black 11



The query message shows the current baud rate. The datafields and their settings are listed in Table 8.5.

Fig.8.8 Syntax for the BAUd command

Fig.8.9 Syntax for the BAUd query message and sound level meter re-sponse


Rate (command) 12244896192

120024004800960019200

Rate (response) 120024004800960019200

Table 8.5 BAUd data fields and codes

930667e


BAUDRate

SP—


SETTING BAUD RATE TO:Rate

930668e


BAUD


BAUD RATE:Rate

SP—

bb090913.book : 2236-ch8 Black 12



CLock

The CLock command message sets the date and time on thesound level meter’s calendar and clock. The query messageshows the date and time on the sound level meter’s calendarand clock. The data fields and their settings are listed inTable 8.6.

Fig.8.10 Syntax for the CLock command

Fig.8.11 Syntax for the CLock query message and sound level meter re-sponse

Field Name Field Setting

Date YYYY-MM-DD

Time HH:MM:SS

Table 8.6 CLock data fields and codes

930669e


CLOCKDate

SP—

TimeSP—

930670/1e


CLOCK


CURRENT DATE & TIME:Date

SP—

TimeSP—

bb090913.book : 2236-ch8 Black 13



CONtinue

The CONtinue command message starts a measurementwithout resetting the sound level meter.

DEFault

The DEFault command message sets the sound level meterto its default set-up.*

* Baud rate and handshake are not affected.

Fig.8.12 Syntax for the CONtinue command

Fig.8.13 Syntax for the DEFault command

930671e


CONTINUE


MEASUREMENTS CONTINUED

930672e


DEFAULT


SET TO DEFAULT SET–UP MEASUREMENT RESETCR—

bb090913.book : 2236-ch8 Black 14



DISp

The DISp command message sets the parameter to be shownon the sound level meter’s screen. The query message showsthe current displayed parameter, its current level and if thesound level meter is or has been overloaded since the lastreset. The data fields and their settings are listed in Table 8.7.

Fig.8.14 Syntax for the DISp command

Fig.8.15 Syntax for the DISp query message and sound level meter re-sponse

930673e


DISPParameter

SP—

930674/2e


DISP


ParameterSPDISPLAYED PARAMETER: dB— SP— SP—

Level

+SP— OVLSP—

* †

* If currently overloaded

If overloaded since last reset†

%

bb090913.book : 2236-ch8 Black 15




Parameter (command) MAXPPEAKSPLMAXLMINLLeqSELLEPdOVLLN1LN2LN3

Set to Leq or LImSet to SEL or IELLEP,d

LN(1)LN(2)LN(3)

Parameter (queryresponse)

MAXPPEAKSPLMAXLMINLLeqLImSELIELLEPdOVLLN1LN2LN3

LeqLIm

LEP,d

LN(1)LN(2)LN(3)

Level XXX.X dB or %

Table 8.7 DISp data fields and codes

bb090913.book : 2236-ch8 Black 16



ELapsed

The ELapsed query message shows the current elapsed meas-urement time. The data fields and their settings are listedin Table 8.8.

Fig.8.16 Syntax for the ELapsed query message and sound level meterresponse


Time HHHH:MM:SS

Table 8.8 ELapsed data fields and codes

930675/1e


ELAPSED


SPELAPSED TIME (HHHH:MM:SS): —

Time

bb090913.book : 2236-ch8 Black 17



ERASE

The ERASE command message erases the selected results.The data field settings are listed in Table 8.16.

Fig.8.17 Syntax for the ERASE command


Result L_RXALL

Logged ResultsRecord No. X (1-40)All Records

Table 8.9 ERASE data fields and codes

960399e


ERASE SP—

Result

bb090913.book : 2236-ch8 Black 18



EXPosure

The EXPosure command message sets the Exposure Time.The query message shows the current Exposure Time. Thedata fields and their settings are listed in Table 8.10.

Fig.8.18 Syntax for the EXPosure command

Fig.8.19 Syntax for the EXPosure query message and sound level meterresponse


Time HH:MM Between 1min and 24hours

Table 8.10 EXposure data fields and codes

930676e


EXPOSURE SP—

Time

930677e


EXPOSURE


EXPOSURE TIME (HH:MM): SP—

Time

bb090913.book : 2236-ch8 Black 19



FOrmat

The FOrmat command message sets the selected Output For-mat. The query message shows the current Output Formatfor the selected results. The data fields and their settings arelisted in Table 8.11.

Fig.8.20 Syntax for the FOrmat command

Fig.8.21 Syntax for the FOrmat query message and sound level meterresponse

930794e


SPFORMAT — SP—

Type Heading

Res.

FormatSP—

SP—

930793e


SP:


FORMAT

—

Type Heading

Res.

FormatSP—

SP SP—

Type

,

dB,

SP—

bb090913.book : 2236-ch8 Black 20



FREE

The FREE query message shows how much time is left inthe sound level meter’s log at the current logging rate, andhow many records are left in the sound level meter’s memory.Together with the BATt command, it is equivalent to theStatus Fast Edit function available from the front plate ofthe sound level meter. The data fields and their settings arelisted in Table 8.12.


Type (command, query) O_RL_RL_DC_D

Overall ResultsLogged ResultsLevel DistributionCumulative Distribution

Format (command)* PR24PRSP

Printer (24 char.)PrinterSpreadsheet

Res.† 15

dB

Heading (command) SHLO

ShortLong

Type (query response) OVERALL RESULTSLOGGED RESULTSLEVEL DISTRIBUTIONCUMULATIVEDISTRIBUTION

Overall ResultsLogged ResultsLevel DistributionCumulative Distribution

Format (query response) PRINTER 24 CHAR.PRINTERSPREADSHEET

Printer (24 char.)PrinterSpreadsheet

Heading (queryresponse)

SHORT HEADERLONG HEADER

* Only available if Type is Logged_Results† Only available if Type is Level_Distribution or Cumulative_Distribution

Table 8.11 FOrmat data fields and code

bb090913.book : 2236-ch8 Black 21



FW

The FW command message sets the frequency weighting ofthe RMS signal. The query message shows the current fre-quency weighting of the RMS signal. The data fields and theirsettings are listed in Table 8.12.

Fig.8.22 Syntax for the FREE query message and sound level meter re-sponse


Log Status HHH:MM

Memory Status XX Records

Table 8.12 FREE data fields and codes

Fig.8.23 Syntax for the FW command

930680e


FREE


FREE LOG: SP— SP—FREE RECORDS:CR—

LogStatus

MemoryStatus

930681/1e


FW


MEASUREMENT RESET

SP—

Status

bb090913.book : 2236-ch8 Black 22



Fig.8.24 Syntax for the FW query message and sound level meter response


Status (command) ACL31*63*12*25*50*1K*2K*4K*8K*

31.5Hz63Hz125Hz250Hz500Hz1kHz2kHz4kHz8kHz

Status (response) ACL31.5 HZ*63 HZ*125 HZ*250 HZ*500 HZ*1 KHZ*2 KHZ*4 KHZ*8 KHZ*

* Only available with sound level meters with filter sets (Types 2236 C–009 and 2236 D–009)

Table 8.13 FW data fields and codes

930682e


FW


FREQUENCY WEIGHTING: SP—

Status

bb090913.book : 2236-ch8 Black 23



HAndshake

The HAndshake command message sets the form of dataexchange over the interface. The query message shows thecurrent status. The data fields and their settings are listedin Table 8.14.

Fig.8.25 Syntax for the HAndshake command

Fig.8.26 Syntax for the HAndshake query message and sound level meterresponse


Status (command) HWXNO

HardwireXON/XOFFNone

Status (response) HARDWIREXON/XOFFNONE

Table 8.14 HAndshake data fields and codes

932125/1e


HANDSHAKEStatus

SP—

932124e


HANDSHAKE


HANDSHAKE:Status

SP—

bb090913.book : 2236-ch8 Black 24



OFf

The OFf command message switches the sound level meteroff. To switch the sound level meter on, send any characterto the sound level meter (e.g. ⟨ Break ⟩).

PAuse

The PAuse command message puts the sound level meter inPause mode. The pause will take effect on the next evensecond of the sound level meter’s clock. Therefore, you mustwait for one full second before sending the next command tobe sure that the pause condition has taken effect.

Fig.8.27 Syntax for the OFf command

Fig.8.28 Syntax for the PAuse command

930683e


OFF


MEASUREMENTS PAUSED SLM OFFCR—

930684e


PAUSE


MEASUREMENTS PAUSED

bb090913.book : 2236-ch8 Black 25



PErcentile

The PErcentile command message sets the selected percen-tile. The query message shows all the current percentiles.The data fields and their settings are listed in Table 8.15.

Fig.8.29 Syntax for the PErcentile command

Fig.8.30 Syntax for the PErcentile query message and sound level meterresponse


No. LN1LN2LN3

LN1 (default L1)LN2 (default L10)LN3 (default L90)

Percent X 1 to 99

Table 8.15 PErcentile data fields and codes

930688e


PERCENTILE SP—

NoSP—

Percent

930689e


SPPERCENTILE LEVELS: L


PERCENTILE

—

Percent

bb090913.book : 2236-ch8 Black 26



PRint

The PRint command message prints the selected results inthe current output format to a connected printer or computer.If no results are selected, the sound level meter prints thelast selected results. The data fields and their settings arelisted in Table 8.16.

To stop a print-out in progress, transmit ⟨Control⟩ + C (i.e.,hexadecimal: 03; or ASCII: ETX).

PW

The PW command message sets the frequency weighting ofthe Peak signal. The query message shows the current fre-quency weighting of the Peak signal. The data fields and theirsettings are listed in Table 8.17.

Fig.8.31 Syntax for the PRint command


Result O_RL_RL_DC_DXALL

Overall ResultsLogged ResultsLevel DistributionCumulative DistributionRecord No. XAll Records

Table 8.16 PRint data fields and codes

930685e


PRINT SP—

Result

bb090913.book : 2236-ch8 Black 27



RANge

The RANge command message sets the measurement range.The query message shows the current measurement range.The data fields and their settings are listed in Table 8.18.

Fig.8.32 Syntax for the PW command

Fig.8.33 Syntax for the PW query message and sound level meter response


Status (command) CL

Status (query response) CLIN

Table 8.17 PW data fields and codes

930686/1e


PW


MEASUREMENT RESET

SP—

Status

930687e


PW


PEAK WEIGHTING: SP—

Status

bb090913.book : 2236-ch8 Black 28



Fig.8.34 Syntax for the RANge command

Fig.8.35 Syntax for the RANge query message and sound level meterresponse


Status (command) 90*100110120130140

10 – 9020 – 10030 – 11040 – 12050 – 13060 – 140

Status (query response) 10 – 90*20 – 10030 – 11040 – 12050 – 13060 – 140

* Only available with sound level meters with filter sets (Types 2236 C–009 and 2236 D–009) whenRMS Frequency Weighting is 31.5Hz – 8kHz

Table 8.18 RANge data fields and codes

930690e


RANGE SP—

Status

930691e


RANGE: SP—

Status


RANGE

bb090913.book : 2236-ch8 Black 29



RESet

The RESet command message resets the sound level meter.

Note: There is no reset warning.

SETup

The SETup query message shows the sound level meter’scurrent set-up. The data fields and their settings are listedin Table 8.19.

Fig.8.36 Syntax for the RESet command

Fig.8.37 Syntax for the SETup query message and sound level meter re-sponse

930693e


MEASUREMENT RESET


RESET

930694/1e


CRMEASUREMENT SET–UP :


SETUP

—

ParameterSP—

Status

bb090913.book : 2236-ch8 Black 30




Parameter FREQUENCY WEIGHTINGPEAK WEIGHTINGTIME WEIGHTINGDISPLAYED PARAMETERRANGECHANGE RANGEPERCENTILE LEVELSAUTO LOGGINGAUTO LOGGING RATEEXPOSURE TIMEAUTO START

Frequency weighting (RMS)Frequency weighting (Peak)

Status A/C/L/XXX HZ*C/LFAST/SLOW/IMPULSE/Q(5ms)XXXXX – XXX dBWITH/WITHOUT RESETLN1 LN2 LN3ON/OFFXXHH:MMON/OFF

See Table 8.12

Displayed Parameter

See Table 8.1

* Only available with sound level meters with filter sets (Types 2236 C–009 and 2236 D–009)

Table 8.19 SETup data fields and codes

bb090913.book : 2236-ch8 Black 31



STOre

The STOre command message saves the overall results tothe next available record.

TW

The TW command message sets the time weighting. Thequery message shows the current time weighting. The datafields and their settings are listed in Table 8.20.

Fig.8.38 Syntax for the STOre command

Fig.8.39 Syntax for the TW command

960400e


STORE

930697/1e


TW


MEASUREMENT RESET

SP—

Status

bb090913.book : 2236-ch8 Black 32



Fig.8.40 Syntax for the TW query message and sound level meter response


Status (command) SFI

SlowFastImpulse

Status (query response) SLOWFASTIMPULSEQ*

* Appears when AUTOLog Rate is 0.1. Cannot be changed while AUTOLog Rate is 0.1 and autolog-ging is active

Table 8.20 TW data fields and codes

930698e


TW


TIME WEIGHTING: SP—

Status

bb090913.book : 2236-ch8 Black 33



VErsion

The VErsion query message shows the version no. and logcapacity, in bytes, of the sound level meter. The data fieldsand their settings are listed in Table 8.21.

Fig.8.41 Syntax for the VErsion query message and sound level meterresponse


Version Status 2236 X–009 X = A, B, C or D

Software Status N.NN (VP XXXX) Values for N.NN and XXXXdepend on version number

Memory Status 128*512†

KBytes

* Available with Precision Integrating Sound Level Meters Types 2236 A–009 and 2236 C–009.Upgrade to 512KBytes available

† Available with Precision Integrating Sound Level Meters Types 2236 B–009 and 2236 D–009

Table 8.21 VErsion data fields and codes

930699/1e


VERSION


VERSION: SP— CR— CR—

VersionStatus

SOFTWARE:

LOGGING MEMORY:

SP—

SP— SP—

SoftwareStatus

MemoryStatus

KBYTES

bb090913.book : 2236-ch8 Black 34


bb090913.book : bb090913_IX.doc Black,Blue 1

BB0909–13 Index – 1Precision Integrating Sound Level Meter Type 2236User Manual

Index

Numerics1/1-octave filter ................................ 3–12, 8–214226, calibration with ................................... 4–34231, calibration with ................................... 4–3

AA, frequency weighting ........... 3–12, 6–4, 8–22AC Output .......................................... 4–16, 6–5Accessories .................................................. 6–10ANSI Draft S 1.43 ......................................... 6–2ANSI S 1.4 ..................................................... 6–2Auto logging ................................................ 3–21

default ...................................................... 3–8effect on time weighting ....................... 3–21

Auto start .................................................... 4–13default ...................................................... 3–8

AUTOLog ....................................................... 8–7AUTOStart .................................................... 8–9

BBack-light .................................................... 3–24Back-up battery ............................................ 3–6BATt ............................................................ 8–10Battery

back-up .................................................... 3–6level ............................................... 4–7, 8–10replacing .................................................. 3–5warnings .................................................. 3–6

BAUd ........................................................... 8–10Baud rate ............................................ 5–6, 8–10BS 2475 .......................................................... 1–3

BS 5969 ................................................ 1–2, 6–2BS 6698 ................................................ 1–2, 6–2Buffer ............................................................. 1–9

CC, frequency weighting .......... 3–12, 3–14, 6–4,

......................................................... 8–22, 8–27Calendar ........................................... 3–18, 8–12

wrong date or time .................................. 3–7Calibration .................................................... 2–3

checking ................................................... 2–7conditions ................................................. 6–5free or diffuse field measurements ......... 4–2nominal level ........................................... 4–3when ......................................................... 4–2

Calibration set-upMultifunction Acoustic Calibrator Type

4226 ....................................................... 4–3Sound Level Calibrator Type 4231 ........ 4–3

Calibrators .................................................... 4–3Changing

batteries ................................................... 3–5displayed parameter ............................. 4–15level, reset due to .................................. 3–10Settings ........................................... 1–4, 1–7

Checkingcalibration ....................................... 2–7, 4–5Settings .................................................... 1–4status ....................................................... 4–7

CLock ........................................................... 8–12Clock ............................................................ 3–18


Index

Index – 2 Brüel & KjærPrecision Integrating Sound Level Meter Type 2236User Manual

Command message overview ........................8–6Computer

control from ..............................................8–4set-up ........................................................8–4transferring results to ...........................5–21

Computer controlswitching on the SLM ............................8–24syntax .......................................................8–4

CONtinue .....................................................8–13Contrast .......................................................3–24Controlling from a computer .........................8–4Controls .............................................................. 5Cumulative Distribution ....................1–9, 5–16

not available ...........................................3–20

DDaily Personal Noise Exposure Level ..........8–3Data ................................................................1–7Date ...................................................3–18, 8–12

wrong date or time ...................................3–7DAT-recorder ...............................................5–25DC Output ..........................................4–16, 6–5DEFault .......................................................8–13Default set-up .....................................3–8, 8–13

switching on in .........................................3–8Diffuse-field calibration ................................4–2Diffuse-field response ....................................6–7Directional characteristics ............................6–8DISp .............................................................8–14Display ............................................................... 5Displayed parameter ........................4–15, 8–14

default ......................................................3–8Distribution

Cumulative ....................................1–9, 5–16Level ..............................................1–9, 5–15

EELapsed .......................................................8–16Elapsed time ................................................8–16ERASE .........................................................8–17Erase ..............................................................5–5Example measurement .................................2–2EXposure ......................................................8–18Exposure Time .........................3–17, 8–3, 8–18

default ......................................................3–8Extension cable, microphone ........................3–3External power supply ..................................3–6

FF, time weighting ........................................3–11Fast edit .........................................................1–7Fast time weighting ....................................3–11Filter .................................................3–12, 8–21

characteristics ..........................................6–3Fitting batteries .............................................3–5FOrmat .........................................................8–19

FREE ............................................................8–20Free memory, log ................................4–7, 8–20Free-field calibration .....................................4–2Free-field response ........................................6–7Frequency analysis, making a ....................4–12Frequency response .......................................6–7Frequency weighting

default (Peak) ...........................................3–8default (RMS) ...........................................3–8Peak .............................................3–14, 8–26reset due to changing .................3–12, 3–14RMS .............................................3–12, 8–21shown on display ........................3–12, 4–16

FW ................................................................8–21

HHAndshake ..................................................8–23Handshake .....................................................5–6Hardwire ........................................................5–6Heading .................................................5–8, 5–9

II, time weighting .........................................3–11IEC 1672 ........................................................6–2IEC 651 ..........................................................6–2IEC 804 ...........................................................6–2Impulse time weighting ..............................3–11Interface set-up ...................................5–6, 8–23

LL, frequency weighting ............3–12, 3–14, 6–4

..........................................................8–22, 8–27LEP,d ..................................................3–17, 8–3Level Distribution ..............................1–9, 5–15

not available ...........................................3–20Light .............................................................3–24Linear frequency weighting ............3–12, 3–14,

.................................................6–4, 8–22, 8–27LN parameters ............................................8–25

not available ...........................................3–20Log ..................................................................1–9

capacity ..................................................8–33capacity left ..............................................4–7free ..........................................................8–20

Logged Results ...........................1–9, 3–21, 8–7erasing ......................................................5–5Interpreting times .................................5–24use in spreadsheet program ..................5–22

Long heading .................................................5–9

MMeasurement .................................................2–6

continue ..................................................8–13elapsed time ...........................................8–16example ....................................................2–2pause ......................................................8–24


Index

BB0909–13 Index – 3Precision Integrating Sound Level Meter Type 2236User Manual

range ............................................. 3–9, 8–27standards, re ......................................... 1–10start automatically ................................ 4–13

Memory .......................................................... 1–9capacity left ............................................. 4–7

Microphoneextension cable ........................................ 3–3mounting ................................................. 3–3response ................................................... 6–7

Mounting the microphone ............................ 3–3Multifunction Acoustic Calibrator Type 4226

setting up for calibration with ................ 4–3

NN.A. ................................................... 3–11, 4–16Nominal calibration level ............................. 4–3None (handshake) ......................................... 5–6

OOctave filter ...................................... 3–12, 8–21OFf ............................................................... 8–24Off ....................................................... 3–9, 8–24On .............................................. 2–2, 3–8, 8–24Ordering information .................................. 6–10Output

AC Output socket .................................. 4–16DC Output socket .................................. 4–16

Output Formats .......................................... 5–10Output formats ............................................. 5–8

checking and changing .............. 5–17, 8–19Cumulative Distribution ...................... 5–16default ...................................................... 3–8Level Distribution ................................. 5–15Printer ........................................ 5–10, 5–19Printer (24 char./line) ..... 5–11, 5–12, 5–19Spreadsheet ................................ 5–13, 5–22

Overall Results ................................... 1–10, 5–9erasing ..................................................... 5–5printing .................................................... 2–8recalling ................................................... 5–4storing ...................................................... 2–7

Overload ...................................................... 3–21indication via interface ......................... 8–14

PParameters

available .................................................. 1–2changing the displayed .............. 4–15, 8–14

PAuse ........................................................... 8–24Pause ........................................................... 8–24

Effect on log times ................................. 5–24Peak frequency weighting ............... 3–14, 8–26

reset due to changing ............................ 3–14PErcentile .................................................... 8–25Percentiles ........................................ 3–15, 8–25

default ...................................................... 3–8

Power supply, external ................................. 3–6Practical hints ............................................. 1–10PRint ............................................................ 8–26Printer (24 char./line) output format ........ 5–11,

................................................. 5–12, 5–19Printer output format ...................... 5–10, 5–19Printing ....................................................... 5–18

Overall Results ........................................ 2–8results .................................................... 8–26stopping ...................................... 5–19, 8–26

PW ............................................................... 8–26

Qq (on display) ............................................... 3–12Quasi-analogue display .....................................5Query message overview .............................. 8–6

RRandom incidence corrector ................ 4–3, 4–9RANge .......................................................... 8–27Range

default ...................................................... 3–8measurement ................................ 3–9, 8–27reset due to change ............................... 3–20

Recall ............................................................. 5–4Recording ..................................................... 5–25Records

erasing ..................................................... 5–5free ........................................................... 4–7recalling results from .............................. 5–4storing results in .......................... 5–3, 8–31

Replacing batteries ....................................... 3–5RESet ........................................................... 8–29Reset ................................................... 4–9, 8–29

at range change ..................................... 3–20default ................................................ 3–8

due to changing measurement range ... 3–10due to changing Peak frequency

weighting ............................................. 3–14due to changing RMS frequency

weighting ............................................. 3–12due to changing time weighting ........... 3–11

Resultserasing .......................................... 5–5, 8–17Logged ........................................... 1–9, 3–21Overall ................................................... 1–10printing .................................................. 8–26recalling ................................................... 5–4storing .................................. 2–7, 5–3, 8–31transfer to computer ............................. 5–21

RMS frequency weighting ............... 3–12, 8–21reset due to changing ............................ 3–12

SS, time weighting ........................................ 3–11Screen contrast ........................................... 3–24


Index

Index – 4 Brüel & KjærPrecision Integrating Sound Level Meter Type 2236User Manual

SEL .................................................................8–2Serial interface ..............................................6–5Service and repair ............................................. 1Setting up .......................................................2–5

computer ..................................................8–4interface .................................................8–23

Settings ..........................................................1–3changing ..........................................1–4, 1–7checking ....................................................1–4overview ...................................................1–6

SETup ..........................................................8–29Set-up ...........................................................8–29

default ...........................................3–8, 8–13Short heading ................................................5–8Sockets ............................................................... 5Sound Exposure Level (SEL) ........................8–2Sound Level Calibrator Type 4231

setting up for calibration with ................4–3Specifications .................................................6–2Spreadsheet output format ..............5–13, 5–22Start measurement automatically ....4–13, 8–9Status ....................................................1–7, 4–7

battery ....................................................8–10STore ............................................................8–31Store ...............................................................5–3Storing Overall Results ......................2–7, 8–31Switching

off ..............................................................3–9on .....................................................2–2, 3–8

Syntaxcomputer control ......................................8–4

TTime ..................................................3–18, 8–12

wrong date or time ...................................3–7Time weighting .................................3–11, 8–31

default ......................................................3–8fixed ........................................................3–12reset due to changing ............................3–11

To .......................................................5–19, 8–26Transferring results to computer ...............5–21Turning

off ..............................................................3–9on ..............................................................3–8

TW ................................................................8–31

VVErsion ........................................................8–33Version no. ...................................................8–33Viewing conditions ......................................3–24

WWeighting

frequency ..................................................6–4frequency, Peak .....................................3–14frequency, RMS ......................................3–12

time .........................................................3–11

XXON/XOFF .....................................................5–6

Documents

Sound Level Meter Baaska